Question

multiple choice question
a certain atom of boron has 5 protons and 6 neutrons. what is its mass number?
o 1
o 5
o 11
o 6

Explanation:

Step1: Recall mass - number formula

The mass number ($A$) of an atom is the sum of the number of protons ($p$) and neutrons ($n$), i.e., $A=p + n$.

Step2: Substitute given values

Given $p = 5$ and $n=6$, then $A=5 + 6=11$.

Answer:

C. 11