Question

Name a species which has only one proton and one electron.

Answer 1

Atomic number:

1. The Atomic number of a species is equal to the number of protons or electrons present in an atom.
2. Therefore, the atomic number of the species will $1$
3. So species will be Hydrogen atom $\left({}_1{}^{1}H\right)$, as it contains one proton, one electron, and zero neutrons.