I. Bohr’s Model / Energy Levels
A. Def – a specific area where an electron is likely to be.
nucleus
2 electrons
8 electrons
18 electrons
32 electrons
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Chapter 4Lesson 2
“A Tour of the Periodic Table”
I. Organization of the P.T.
A. Periodic Law1. Def – Elements are arranged according
to properties.2. Ex: Group 1 Elements Video3. Periods – horizontal4. Group – Vertical
a. Aka family
II. Ions
A. Def – an atom that gains or loses electrons. Will have a negative or positive charge.
B. Ex: Fluorine (pg. 115)
F2e7e
e
8e
What kind of charge willfluorine have now as an ion?
1-
III. Atomic Number
A. Def – the # of protons in an atom’s nucleus.
B. On P.T. – located right above the chemical symbol
*Protons dictate the type of element we have**Electrons always equal the # of protons in a
neutral atom*
IV. Mass Number
A. Def – The sum of protons and neutrons in the nucleus of an atom.1. On P.T. – bottom number
-round up/down2. Ex: What is the mass number of the following elements?
Carbon OxygenIron CalciumSodium Zinc
12
56
23
16
40
65
3. Mass # = Protons + Neutrons
4. How many Neutrons on average are found in the following elements?Boron FluorineSilicon CopperSilver Gold 118
14
6
61
10
35
V. Isotope
A. Def – An atom that has a different number of neutrons.1. Does not affect the element2. Only changes the weight of the element
3. Ex: Boron-10 and Boron-11
p p p p p p p p p p
n n n n nn n n n n n
5 protons 5 protons
5 neutrons 6 neutrons
This meansthe mass #
Boron-10 Boron-11
4. How many neutrons do the following isotopes have?
Oxygen-14Titanium-50Magnesium-22Potassium-43Aluminum-23Iodine-130
6
28
10
24
10
77
VI. Average Atomic MassA. Def – average mass of all isotopes of one
element combined.1. Found on P.T. underneath chemical symbol.2. Ex: Carbon = 12.011
“Carbon has 3 known isotopes. Carbon-12, 13, and 14. Carbon-12 makes up 99% of all carbon on earth. Carbon-13 and 14 make up 1%.”
Why?