Question

an ion X with charge -2 contains 10 electrons and 8 neutrons what are the mass number and atomic number of the element X?

Answer 1

Nitrogen. Every element has a specific numbers of protons and electrons and are consistent for every atom of the element. Neutrons who with protons form the atomic mass of an element may change. Elements with same number of protons but different number of neutrons are called isotopes.

Nitrogen 10 - 7 protons, 3 neutrons,

Nitrogen 11 - 7 protons, 4 neutrons,

Nitrogen 12 - 7 protons, 5 neutrons,

Nitrogen 13 - 7 protons, 6 neutrons,

Nitrogen 14 - 7 protons, 7 neutrons (most commonly used weight.),

Nitrogen 15 - 7 protons, 8 neutrons,

all the way to

Nitrogen 25 - 7 protons, 18 neutrons.

Answer 2

mass no =16
atomic no =8