#### Transcript Notes Unit 3-1

```Warm Up
9-28-16
1. Name one concept that you remember how
to do from Unit 1 (prepare to explain)
2. Name one lab that we did in Unit 2
3. How do we organize the periodic table?
Agenda
Homework
Turn in Current Event Article Today - Test correction
WS Subatomic Heavyweight
Go over Test Unit 2
Notes Unit 3-1
WS Subatomic heavyweights
Test Results
 Average Unit 1 = 77%
 Average Unit 2 = 83%
Test Unit 2 Most Missed Qs’
 The law of conservation of mass
states
A. Atoms of different elements have different
properties
B. Atoms can’t be destroyed in a chemical
reaction
C. Matter is composed of atoms
D. Atoms can’t be divided
Test Unit 2 Most Missed Qs’
 Most of the volume occupied by a
piece of copper is taken up by the
volume of the copper nucleus
A. True
B. False
Test Unit 2 Most Missed Qs’
 For an electron in an atom to change
from the ground state to an excited
state
A. Energy must be released
B. Radiation must be emitted
C. Electron transition from higher level
to lower energy level
D. Energy must be absorbed
Unit 3-1
The Periodic Table
How would you organize the
following (16) items?
Screw
driver
Nuts
Clamp
allen
wrench
Pliers
Drill
Wrench
Box
cutter
Periodic Law
 Periodic law - periodic
table is organized based
on the atomic #, chemical
& physical properties of
the elements
 Mendeleev is the creator
of the periodic table used
atomic mass
The Periodic Table
 Group or family
 A vertical columns
 Elements in a group share the same chemical
properties
 Period
 A horizontal rows
 Elements are in the same energy level
(electron shell)
The Periodic Table
 Elements’ chemical properties & reactivity
are determined by the number of valence
electrons
 Valence electrons are electrons that are in
the outermost energy level of an atom
(in the S and P orbital only)
e-
e-
e-
e-
e-
e-
The Periodic Table
Check-In
 How many groups are on the periodic
table?
 Elements in group #18 will have ______
valence electrons
 How many valence e- are in Ca, Ge and F?
Average Atomic Mass vs. Mass
Number
What is the mass of neon element?
Average Atomic Mass vs. Mass
Number
 The average atomic mass is the average of
the mass numbers of all the isotopes of
that element.
Average Atomic Mass and Mass
Number
What is the average mass of Lead? Based
on the given stable isotopes
Name of
Atom
Abundance
Percent %
1.4
24.1
22.1
52.4
Mass x
Percent
204 x 0.014
206 x 0.241
207 x 0.221
208 x 0.524
= 2.856
= 49.646
= 45.747
= 108.992
Total =
Assignments
 Summary - Compare valence electrons
with total electrons. Why are valence
electrons important?
 WS Subatomic
heavyweights
due next class
```