Subatomic Particles Worksheet
Fill in the blanks for the elements in this chart. Please keep in mind that the isotope represented by each
space may NOT be the most common isotope or the one closest in atomic mass to the value on the periodic
table.
Element
aluminum
Chemical
Notation
27
13
Number of
Protons
Number of
Electrons
Number of
Neutrons
Atomic
Number
Mass
Number
Al
beryllium
5
18
carbon
17
20
19
4
2
41
He
lithium
0
12
neon
15
7
N
8
14
16
11
sodium
11
1. What is the atomic number of oxygen (O)?
2. How many protons does an aluminum (Al)
atom have?
3. How many electrons does a calcium (Ca) atom
have?
For #4 – 6, consider a potassium (K) atom with a
mass number of 40:
4. How many protons does this atom have?
5. How many electrons does this atom have?
6. How many neutrons does this atom have?
For #7 – 9, consider the atom with A = 95 and
Z = 42:
7. How many neutrons does this atom have?
8. How many protons does this atom have?
18
23
13
9. What is the chemical symbol for this element?
For #10 – 12, consider the atom with 35 protons,
35 electrons, and 45 neutrons:
10. What is the chemical symbol for this
element?
11. What is the atomic number of this atom?
12. What is the mass number of this atom?
For #13 – 15, consider a copper (Cu) atom with a
mass number of 64:
13. What is the Z value for this atom?
14. What is the A value for this atom?
15. How many neutrons does this atom have?