What is the Atomic Mass of Beryllium?

Atomic Mass of Beryllium is  .

A) 8

B) 10

C) 9

D) 11

Answer: The atomic mass of Beryllium is 9 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 Beryllium,

• Number of protons =  4
• Number of Neutrons = 5

Thus,

Atomic Mass of Beryllium = 4 + 5 = 9

In absolute terms, the average atomic mass of Beryllium is 9.012182 amu. It is calculated taking into account all the isotopes of Beryllium.

Beryllium has twelve isotopes, but commonly only three stable isotopes are considered that are,

• ⁷Be
• ⁹Be
• ¹⁰Be