1. Unit 6, Lesson 2: Structure of the Atom

2. Structure of the Atom This should be review from last year!
Please read and complete the Atomic Structure worksheet.
Go over first row, then allow students to work min

3. Element or Ion
Atomic Number
Mass Number
# of Protons
# of Neutrons
# of Electrons Li 3 7 4
Ba2+ 56
137 81 54
Al3+ 13 27 14 10 F- 9 19 Br 35 80 45
Ru3+ 44
101 57 41
Cr2+ 24 52 28 22
S2- 16 32 18 Si C 6 12
P3- 15 31

4. Brain Break!

5. Isotopes
The number of protons in an atom is definitive of that atom, but the number of neutrons can vary.
Isotopes are atomic species having the same atomic number but different atomic masses.

6. Natural Mixtures of Isotopes
The mass numbers on the periodic table represent the average values for the mixtures of isotopes that occur in nature.
Example: Experiments show that naturally occurring chlorine is a mixture which is 75.77% Cl-35 and 24.23% Cl-37. What is the expected molar mass of chlorine?
Assume 1 mol total, calculate mass of each, then add them together. – 15 min

7. Homework:
Pg. 150 #23
5 min