Question

The first period has how many orbitals?

Answer 1

• An orbital is a three-dimensional space around the atomic nucleus where the probability of finding an electron is maximum.
• The first period has only one $s$ orbital and it can accommodate a maximum of two electrons.
• The first period contains only two elements that are: Hydrogen$\left(\mathrm{H}\right)$ and Helium $\left(\mathrm{He}\right)$.
• The electronic configuration for hydrogen is $1{\mathrm{s}}^1$ and for helium, it is $1s^2$.

Hence, the first period has only one orbital.