Question

The mass number $A$ of an atom is equal to the ___________.

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

Answer 1

The correct option is C Number of protons $+$ neutrons

${}_Z{X}^A$

$A\to$ mass number

$A\to$ no. of protons $+$ neutrons