Question

The ratio of the atomic numbers of two elements A and B is 2 : 3. A is an inert gas with the first 3 orbits completely filled. Identify A and B and write their electronic configurations.

Answer 1

1. Electronic configuration: It is a method to show the distribution of electrons in an atom.
2. The electrons are formally situated in these subshells and the notations aid in determining their positions and the electrical configuration.
3. Since $A$ is an inert gas with an entirely filled first three orbits, its electronic configuration is $2,8,18,8$.
4. In the neutral atom, the total number of protons equals the total number of electrons. As a result, the inert gas A's atomic number is = $\mathrm{Atomic}\mathrm{number}=2+8+18+8=36$.
5. And the ratio of the atomic numbers of two elements $A$ and $B$ is 2 : 3.
6. So, the atomic number of element $B$= $\frac{3}{2}\times 36=54$.
7. Hence, the electronic configuration of $B$is $2,8,18,18,8$.
8. The atomic number of $A$is $36\left(Kr\right)$and its electronic configuration is $2,8,18,8$.
9. The atomic number of $B$is $54\left(Xe\right)$and its electronic configuration is $2,8,18,18,8$.