Question

an aluminium isotope has 13 protons, 13 electrons, and 14 neutrons. what is its mass number?
a. 13
b. 26
c. 27
d. 40

Explanation:

Step1: Recall the formula for mass number

Mass number \(A=\) number of protons \(Z+\) number of neutrons \(N\)

Step2: Substitute the given values

Given \(Z = 13\) (protons) and \(N=14\) (neutrons), then \(A=13 + 14\)

Step3: Calculate the result

\(A=27\)

Answer:

C. 27