What is the Atomic Mass of Aluminium?

Atomic Mass of Aluminium is .

A) 26

B) 25

C) 27

D) 28

Answer: The atomic mass of Aluminium is 27 amu. Therefore, the correct option is C.

Explanation:

Atomic Mass of any substance is the sum of the number of protons and the number of neutrons in the nucleus of that atom.

For Aluminium,

• Number of Protons = 13
• Number of Neutrons = 14

Thus,

Atomic Mass of Aluminium = 13 + 14 = 27

In absolute terms, the average atomic mass of aluminium is 26.981 amu. It is calculated taking into account all the isotopes of Aluminium.

Aluminium has 9 isotopes and the two main Isotopes of Aluminium are:

• ²⁶Al
• ²⁷Al  (Stable)