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.
ELEMENTS
aluminum
beryllium
CHEMICAL
NOTATION
27
13
NUMBER NUMBER
NUMBER
ATOMIC
OF
OF
OF
NUMBER
PROTONS ELECTRONS NEUTRONS
13
13
14
13
MASS
NUMBER
26.982
Al
Be
4
2
5
4
9.012
Boron
B
5
2
6
5
10.81
Argon
Ar
18
18
22
18
39.948
carbon
C
6
2
6
6
12.011
Calcium
Ca
20
17
20
20
40.078
Potassium
K
19
19
20
19
41
4
2
2
2
2
4.0026
Helium
2
He
lithium
Li
3
2
4
3
6.94
Hydrogen
H
1
1
0
1
1.008
Magnesium
Mg
12
12
12
12
24.305
neon
Ne
10
2
10
10
20.180
Nitrogen
15
N
7
7
7
7
14.007
7
Oxygen
O
8
2
8
8
18
Silicon
Si
14
14
16
14
28.085
Sodium
Na
11
11
13
11
23
Na
11
11
13
11
22.990
sodium
1. What is the atomic number of oxygen (O)?
8
2. How many protons does an aluminum (Al) atom have?
13
3. How many electrons does a calcium (Ca) atom have?
17
For #4 –6, consider a potassium (K) atom with a mass number of 40:
4. How many protons does this atom have?
20
5. How many electrons does this atom have?
20
6. How many neutrons does this atom have?
20
For #7 –9, consider the atom with A = 95 and Z = 42:
7. How many neutrons does this atom have?
31
8. How many protons does this atom have?
21
9. What is the chemical symbol for this element?
Mo
For #10 –12, consider the atom with 35 protons, 35 electrons, and 45
neutrons:
10. What is the chemical symbol for this element?
Br
(Bromine)
11. What is the atomic number of this atom?
35
12. What is the mass number of this atom?
79.904
For #13 –15, consider a copper (Cu) atom with a mass number of 64:
13. What is the Z value for this atom?
64
14. What is the A value for this atom?
64
15. How many neutrons does this atom have?
93