Element A has 15 protons. Determine the number of neutrons in its isotope with mass number 33.

A) 15

B) 18

C) 33

D) 48

the answer is B your welcome

In an electrically neuteral atom, number of protons = number of electrons = atomic number.

Mass number = neutrons + protons/electrons/atomic number

Therefore,

neutrons = mass number - protons/electrons/atomic number

Neutrons = 33 - 15 = 18

The answer is thus B. But this is the solution and explanation along with it as proof.