Question

An element has 23 electrons and 25 neutrons, its mass is *

Answer 1

Mass of atom is the sum of it protons and electrons. In a neutral atom, the amount of electrons is the same as its protons.

23 electrons = 23 protons (assuming its neutral)

23 Protons + 25 Neutrons= 48 atom mass.

Remember, an electrons mass is so insignificant (About 1/1836 of a protons mass) that it doesn't really play a part in an atom's mass. Therefore, the atom's mass is 48.