List of Mass Numbers of First 20 Elements
The mass number and the atomic number of different elements of the periodic table are as follows,
|
Element |
Symbol |
Atomic Number (Z) |
Mass Number (A) |
Number of Protons |
Number of Electrons |
Number of Neutrons (A-Z) |
|---|---|---|---|---|---|---|
|
Hydrogen |
H |
1 |
1 |
1 |
1 |
0 |
|
Helium |
He |
2 |
4 |
2 |
2 |
2 |
|
Lithium |
Li |
3 |
7 |
3 |
3 |
4 |
|
Beryllium |
Be |
4 |
9 |
4 |
4 |
5 |
|
Boron |
B |
5 |
11 |
5 |
5 |
6 |
|
Carbon |
C |
6 |
12 |
6 |
6 |
6 |
|
Nitrogen |
N |
7 |
14 |
7 |
7 |
7 |
|
Oxygen |
O |
8 |
16 |
8 |
8 |
8 |
|
Fluorine |
F |
9 |
19 |
9 |
9 |
10 |
|
Neon |
Ne |
10 |
20 |
10 |
10 |
10 |
|
Sodium |
Na |
11 |
23 |
11 |
11 |
12 |
|
Magnesium |
Mg |
12 |
24 |
12 |
12 |
12 |
|
Aluminum |
Al |
13 |
27 |
13 |
13 |
14 |
|
Silicon |
Si |
14 |
28 |
14 |
14 |
14 |
|
Phosphorus |
P |
15 |
31 |
15 |
15 |
16 |
|
Sulfur |
S |
16 |
32 |
16 |
16 |
16 |
|
Chlorine |
Cl |
17 |
35 |
17 |
17 |
18 |
|
Argon |
Ar |
18 |
40 |
18 |
18 |
22 |
|
Potassium |
K |
19 |
39 |
19 |
19 |
20 |
|
Calcium |
Ca |
20 |
40 |
20 |
20 |
20 |
Mass Number
Mass Number of an atom is the total number of protons and neutrons present in an atom. We know that an atom consists of electrons, protons, and neutrons but the mass of the atom is contributed by protons and neutrons as the mass of electrons is very low hence it doesn’t contribute to the mass of an atom. In this article, we will learn what is the mass number, the mass number definition, the mass number formula, and the mass number of some commonly known elements.