Question

Total number of orbitals associated with third shell will be_______

Answer 1

Principal quantum number:

• Principal quantum numbers are denoted by the symbol ‘$\mathrm{n}$’. They designate the principal electron shell of the atom.
• For example, Helium$\left(\mathrm{He}\right)$ has an atomic number $2$ and its electronic configuration is $1s^{\mathit{2}}$ and has a principal quantum number $1$.

Total number of orbitals:

• The number of orbitals associated with the principal quantum number $‘\mathrm{n}’$is given by ${\mathbf{n}}^{\mathbf{2}}$.
• For example, the number of orbitals in the case of Helium$\left(\mathrm{He}\right)$ will be ${\left(1\right)}^2$ i.e. $1$.

Given: In the third shell ($\mathrm{n}=3$), there are $3s$ orbital, $3p$orbitals and $3d$ orbitals.

Therefore, the total number of orbitals in the third shell by using the above formula is ${\left(3\right)}^2=9$

Thus, the total number of orbitals associated with the third shell will be $\mathbf{9}$.