Question

what is the mass of an atom with 5 protons, 7 neutrons, and 5 electrons?
17
5
10
12
7

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). Electrons have negligible mass and are not considered in the mass - number calculation. The formula is $A=p + n$.

Step2: Substitute given values

Given that $p = 5$ and $n=7$, we substitute these values into the formula: $A=5 + 7$.

Step3: Calculate the mass number

$5+7 = 12$.

Answer:

12