Question

protons: 5
neutrons: 5
electrons: 5
what is the mass number? 0

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). The formula is $A=p + n$.

Step2: Substitute given values

Given that $p = 5$ and $n = 5$. Then $A=5 + 5$.

Step3: Calculate the result

$A = 10$.

Answer:

10