Question

The number of electrons ,protons and neutrons in a species are equal to 18, 16 and 16 respectively. Assign the proper symbol to the species.

Answer 1

As we know that atomic number is equal to number of protons = 16
Atomic mass number is equal to protons number + neutrons number = 16 + 16 = 32
An element with atomic number 16 and mass number 32 is Sulphur.
But the species is not neutral because the number of protons are not equal to number of electrons.
18 electrons – 16 protons = 2 electrons
It has excess 2 electrons hence it is an anion.
Symbol is 3216S-2