Question

An atom of a mystery element contains 7 protons, 7 neutrons, and 7 electrons.

What is the mass number?
A. 14
B. 7
C. 0
D. 21

Answer 1

A-14

Step-by-step explanation:

Mass number (MN) = Proton number + Neutron number

MN=7+7

MN=14