Download Counting Sub Atomic Particles Atomic Number Mass number

Unit 3—Atomic Theory and the Periodic Table
Name
Pre-AP Chemistry: Worksheet #3.2
Class Period
Date
Counting Sub Atomic Particles
1.
Would you expect two electrons to attract or repel each other? Explain
2.
Why is an atom electrically neutral?
3.
Complete this table.
Atomic
Number
Mass
number
Number of
protons
9
Number of
neutrons
10
14
47
55
15
25
25
Number of
electrons
Hyphen
Notation
Nuclear
Symbol