Elements X, Y, Z have atomic numbers 6, 9 and 12 respectively. Which one :

(i) forms anion – negative ion;

(ii) forms cation – positive ion;

(iii) has 4 electrons in the outermost orbit.

Define the terms : atomic number, mass number and electron.

Sulphur has an atomic number of 16 and a mass number of 32.
State the number of protons and neutrons present in the nucleus of sulphur.