Question

Give the electronic configuration of a positively charged ${\mathrm{Al}}^{3+}$? What would be its atomic num­ber ?

Answer 1

Electronic configuration of ${\mathrm{Al}}^{3+}$:

1. The distribution of electrons in various energy levels or shells of an atom of the element is called electronic configuration.
2. The atomic number of aluminium is $13$.
3. After losing three electrons, aluminium gains $+3$ charge and the remaining electrons are $10$.
4. Therefore, the electronic configuration of ${\mathrm{Al}}^{3+}$ is $(2,8)$.

Atomic number of ${\mathrm{Al}}^{3+}$:

1. Atomic number is equal to the number of protons or number of electrons in the atom in its neutral state.
2. Number of protons in neutral state of ${\mathrm{Al}}^{3+}$ i.e. $\mathrm{Al}$ are $13$
3. Thus, the atomic number of ${\mathrm{Al}}^{3+}$ is $13$.