Atomic+Structure+&+Periodic+Table

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=Guide =

Lesson #5 - Predicting Periodic Trends
** What you Need to Know ** = =

Atomic structure appears on the AP Chemistry exam in about 7 of the 75 multiple choice questions and is almost always included in the free-response section. You need to to be able to understand all of the content under each section review that is listed in this review. Focus on the most difficult elements of this unit, electronic configurations and then work on the history of the atom and the periodic table.

You need to be able to comfortably identify the symbol, atomic number, molar mass, and the atomic weight when presented with an element. The Periodic Table is the most important tool you will need to master for this examination. This is where we will discuss any other pertinent information on how to properly study for this section and what to focus on.

>  >
 * Recall a very brief history of Atomic Theory
 * Know and understand the five main aspects of Dalton's Atomic Theory
 * Recall some of the experiments that led to the identification of sub-atomic particles
 * Know the three particles that make up the atom and their relative charges, masses and positions in the atom
 * Be able to use the Atomic # and Mass # of an isotope to calculate the numbers of protons, neutrons and electrons present
 * Know what the term isotope means and be able to perform simple calculations relating to isotopic data
 * Understand the phenomenon of radioactivity and the properties of radioactive particles
 * Be able to write nuclear equations
 * Understand the concept of half-life and be able to perform calculations related to it
 * Recall some uses of radioactivity
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Understand the term mass deficit
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Be able to use neutron:proton ratio to make predictions about stability
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Understand the terms nuclear fission and fusion
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Understand, that in very general terms, radioactivity involves the rearrangement of the nucleus and chemical reactions involve the rearrangement of electrons
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Know the approximate locations of metals, non-metals and metalloids on the periodic table
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Understand the meaning of the terms Molecule and Ion
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Learn the lists of common anions and cations (including polyatomic ions) studied in TOPIC 2
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Know how to combine those anions and cations in the correct proportions to form ionic compounds with no net charge
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Be able to name binary ionic compounds of a metal and a non-metal
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Be able to name binary molecular compounds of two non-metals
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Be able to name simple binary acids
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Be able to name ionic compounds containing polyatomic anions
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Be able to name oxoacids and compounds containing oxoanions
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;"> Be able to name hydrated salts

= = = = =<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">﻿Lesson #1 - The Periodic Table =

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">**A. The Periodic Table was created by: Mendeleyev and Mayer independently**

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">B. Elements are arranged in rows and columns sequentially by their unique atomic number
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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">C. Atomic number is the number of protons in an element
<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">So if you know the atomic number, you can find the element and if you know the element, you can find the atomic number in the periodic table.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">D. Molar mass or atomic weight of an element is noted below the element symbol
<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">So for carbon, atomic number (=number of protons)=6, atomic weight or molar mass = 12.0, Symbol = C

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">E. Mass number of an atom = number of protons + number of neutrons
<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">This is not given in a typical periodic table, but will be given to you in a problem.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">F. VERY IMPORTANT: Atoms are electrically neutral
<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Number of neutrons = number of protons. Ions are when an atom loses (positively charged ion) or gains an electron (negatively charged ion).

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">G. Isotopes have the same number of protons but different numbers of neutrons
<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Isotopes have different mass numbers.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">H. Elements in the same column belong to a group
<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Elements on the same row belong to the same period. More on periodic table after atomic structure.

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 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 20px; margin: 0px; padding: 5px 0px 0px;">Lesson #2 - Understanding Electronic Configurations **

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">A. Electrons are negatively charged and have negligible mass.
===<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">B. After Schroedinger's Equation and Planck's Quantum theory, picture the electron as behaving as a particle at times and as a wave function at times. ===

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">C. Electrons are described in terms of four quantum numbers.

 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">The set of 4 quantum numbers is unique for each electron, it is like an address.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">You need to remember their names, the range of values.

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 5px 0px 0px;">**D. Principal Quantum Number n = 1,2,3.**
> <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;"> the further the electron is from the nucleus.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">For each atom, the PQN gives you the shell.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">This tells you the distance from the nucleus and the energy.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">The greater the distance from the shell, the higher the energy and

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**E. Angular Momentum Quantum Number** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">electron). l can be 0 to n-1.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Gives you the shape of the electronic orbital (space occupied by the
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">l=0 s subshell, spherical shape
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">l=1 p subshell, dumbell shape
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">l=3 d subshell (too complex, sort of dumbbell)


 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">For n=1, l=0 (The first shell only has s orbitals)
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">n=2, l=-0,1 (The second shell has s and p orbitals)
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">n=3 l= 0,1,2 (The third shell has s, p and d orbitals

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**F. Magnetic Quantum number ml = -l to +l. gives the orientation of the orbital.** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">axes. Important to remember that they all have the same energy or > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">degenerate > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">energy even though they have different orientation.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">For l=0, or s orbital, ml = 0
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">l=1, p orbitals, ml = -1,0,+1. 3 p orbitals, pointing along x, y and x
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">l=2 d orbitals, ml =-2 to +2. 5 d orbitals.. Again all have the same

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 5px 0px 0px;">**G. Spin Quantum number ms = -1/2 or +1/2**

 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; font-weight: normal; line-height: 24px; margin: 0px; padding: 5px 0px 0px;"> An electron can only have two possible spins.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; font-weight: normal; line-height: 24px; margin: 0px; padding: 5px 0px 0px;"> An orbital can accommodate two electrons total, one with positive spin and one with negative spin.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**H. AUFBAU Principle** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">subshells and shells in order of increasing energy.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">In a multi electron atom, electrons have to be placed in orbitals,
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Lowest energy orbitals get filled first then the next higher ones.

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**I. Pauli Principle** <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">No two electrons of an atom can have the exact same set of 4 quantum numbers.

=<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 5px 0px 0px;">**Lesson #3 - Predicting Electronic Configurations** =

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**A. Use the periodic table to get you started.** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">shown. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">etc. There are some exceptions that testers love to put on the exam, > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">and we will go over them, but study this PT carefully. You will need > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">to remember this structure.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">The electrons are added sequentially from left to right in the order
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">1s, then 2s, then 2p, then 3s, then 3p, then 4s,then 3d, then 4p etc

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">Period 1: n=1 <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">Period 2: n=2 (2s and 2p subshells get filled) <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">Period 3: n=3 (3s and 3p get filled, 3d gets filled in the fourth period.) <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">Period 4: n=4 (4s, 3d and 4p get filled) <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">Period 5: n=5 (5s, 4d, 5p get filled)

> <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">to 4 are called p block. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">block or transition elements.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">For this reason Group 1 and 2 are called s block elements. Group 3
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">The middle section where the d orbitals are getting filled are called d

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**B. When you Need the Electronic Configuration of an Atom** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">electrons.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Find it on the PT. Lets say Carbon. It is in period 2, group 4. It has 6
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Start with 1s2, that leaves 4 electrons. Two more in 2s2.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Leaving the 2p orbital which has 2 electrons. So 1s2, 2s2, 2p2.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**C. Selenium 34** <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 43d10, 4p4.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**D. Hund's rule** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">orbital first, singly. Only if there are no empty orbitals will electrons > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">pair up. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">slightly more stable than others.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">When you have p and d orbitals, electrons will occupy an empty
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">C ompletely empty, completely filled and half filled orbitals are
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Completely filled shells are very stable.

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**So the electronic configuration of copper is 4s2 3d10 not 4s13d9.** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Carbon with 2p4 (you have to pair one electron) > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">shell) > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">questions related to Periodic Properties (Ionization energies for > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">example)
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">The energy of Boron with 2p3 (half filled) is slightly lower than
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">And neon and the rest in this group are very stable (completely filled
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">You should remember this because you will need this logic to answer

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**E. Diamagnetism Paramagnetism** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">diamagnetic.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">When you have an unpaired electron, the element is paramagnetic.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">When you have no unpaired electrons, the element is diamagnetic.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Boron and Carbon are paramagnetic. Helium and Beryllium are

=<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 5px 0px 0px;">Lesson #4 - History of the Atom =

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**A. Dalton** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">ratios. So water is always 2H to 1 oxygen.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Atoms are the smallest indivisible part of an element.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Atoms of different elements look different
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Compounds are formed when atoms come together in the same
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Atoms are never created or destroyed in a chemical reaction.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**B. Thomson** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">deflected by electrical fields. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">(protons) charged particles > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">chocolate chips representing the electrons.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Performed experiments with a cathode rays and how they were
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Said that atoms were made up of negative (electrons) and positive
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">He said the atom looked like a chocolate chip cookie with the

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**C. Milliken's Experiment** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">charged oil drops in an electric field.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Determined the charge on an electron by examining the behvior of

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**D. Rutherford** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">gold foil. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">the center and the rest was mostly empty space. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">almost all the mass and that very small negatively charge electrons > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">move around the central nucleus.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Rutherford fired alpha particles (positively charged Helium ions) at
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Most went through, some deflected 180 dgrees.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Told him that all the positive charge of the atom was concentrated in
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">He concluded that there is a positively charged nucleus that contains

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**E. Planck** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">the notion that energy is delivered in small packets, each packet has > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">an energy of E=hv.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Max Planck proved that electromagentic energy is quantized, that is
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">So energy changes occur in steps or multiples of E=hv.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**F. Bohr** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">specific radii, like the planets orbiting the sun.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Bohr then predicted that electrons moved around the atom only in
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">The Bohr model worked for one electron atoms only.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**G. Heisenberg Uncertainty Principle** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">electron at a particular instant. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">we can calculate the probabilities that the electron will be in some > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">part of space.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">It is impossible to know both the position and momentum of an
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">So we cannot really know the orbits or electrons specifically, instead
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">This probability function is called an electronic orbital.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**F. deBroglie Hypothesis** > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">the wavelenght.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">All matter has wave characteristics.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">The equation l = h/mv tells you that the larger the mass, the smaller
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Hence macroscopic bodies have infinitely small wavelengths.

=<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 5px 0px 0px;">**Lesson #5 - Predicting Periodic Trends** =

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====<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; font-weight: normal; margin: 0px; padding: 5px 0px 0px;">**B. The closer the electrons are to the nucleus, the stronger they are attracted to it and the lower the energy** ====

====<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; font-weight: normal; margin: 0px; padding: 5px 0px 0px;">**C. As you add more shells the size of the atom increases, or electrons in n=3 further away from nucleus (and higher in energy) than electrons in n=2. ** ====

====<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; font-weight: normal; margin: 0px; padding: 5px 0px 0px;">**F. Electrons on the outer shells of an atom, the valence electrons, are protected from the positive pull of the nucleus by the intervening electrons.** ====
 * ====<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px;">This is called shielding. They feel less of an attraction than an inner electron. ====

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">//So putting this all together://

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">Atomic radius is the distance from the center of the nucleus to the valence electrons.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**Left to right on a period, Li to Ne, atomic radius decreases**
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Why: electrons are added to the same shell, more protons pulling on them closer to the nucleus.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**Moving down a group: Li to K size increases.**
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Why: Each period adds a new shell, so size increases

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**Cations are smaller than the atoms**
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Why: An electron is lost to make a cation. Sometimes an entire shell is lost when you lose an electron, this will decrease the size. Also the net positive pull increases and pulls the remaining electrons closer.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**Anions are usually larger than the atoms**
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Why: When you add an electron to a valence shell that already has electrons, there is an increased electronic repulsion, and this repulsion increases the size.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; font-weight: normal; margin: 0px; padding: 5px 0px 0px;">**G. Ionization Energy**
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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">**Definition:** This is the energy required to remove an electron from the outermost orbitals of an atom or ion. The first I.E. is when you remove an electron from an atom, second IE is when you remove the second electron now from an ion etc.


 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Left to Right across a period, IE increases **
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Why: Protons are being added as you go from left to right, the positive pull increases, and hence in general the IE increase.


 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Exceptions: **
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">IE of Group 2 (Be) more than Group 3 (B) because in 3A a p electron is being removed in 2A, a s electron. A p electron is further away from the nucleus and shielded by the s orbitals so easier to remove this one.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Group 4 (C) is less than Group 3 (B) because in Carbon you are removing an electron which has paired and leaving a half filled lower energy configuration which is more favorable.


 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Down a group: IE decreases **
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Size of the atoms increases as new shells are added at each level, decreased positive pull of the nucleus, which is now further away from the electron.


 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Second IE is greater than First IE **
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">When an electron is removed, there is a decrease in the electron electron repulsion, and the rest of the electrons move closer to the nucleus. There is now a stronger positive pull leading to a greater second IE
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">When a shell is removed, the next IE is a lot higher than the previous ones, because you are taking an elevtron crm an inner and stable closed shell.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">So Na 2nd IE>>> 1st IE
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Mg 3rd IE >>> 1st and 2nd IE


 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">H. Electron Affinity is the energy released when an electron is added to an atom. **

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<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px;">When the resulting electronic configuraition is more stable than the atom, more energy is given off. This is the case with Group VII or Group VI elements. The addition of an electron or two results in a closed shell, more lower energy sitation. When the resulting ion is less stable, then you have to provide it with energy because the electron must be placed in a higher energy shell. This is the situation in a noble gas, for example adding an electron to a Neon would need to add a new shell. > <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">increases.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">Usually the energy released when you move from left to right
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; line-height: 24px; margin: 0.5em 0px 0px; padding: 0px 0px 0px 3em;">When you go down a group, EA doesnt change a whole lot.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px; margin: 0px; padding: 0px;">**K. Electronegativity**

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 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">The measure of how strongly an atom in a bond is able to attract the electron pair towards itself.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Remember this applies to a pair of atoms in a bond. Typically Electronegativity increases from left to right and from bottom of a group to the top.
 * <span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Remember that the most electronegative elements are found in the top right corner of the PT (O,N and F are the most electronegative elements)

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 16px;">Here is a graphic that summarizes all this: