Question

Atomic mass = ______

• A. Number of protons + Number of neutrons
• B. Number of electrons + Number of neutrons
• C. Number of electrons + Number of protons
• D. Atomic number + Number of neutrons

Answer 1

Answer: (A), (B), (D)

The correct options are
A

Number of protons + Number of neutrons

B

Number of electrons + Number of neutrons

D

Atomic number + Number of neutrons

Atomic mass = Number of protons + Number of neutrons

But in an atom, number of protons = number of electrons = atomic number(Z)

So atomic mass can also be written as:

Atomic mass = Number of electrons + Number of neutrons

Atomic mass =Atomic number(Z) + Number of neutrons