Name a nonmetal which has only one electron in its outermost shell.

• Non-metals are electro-negative because they are formed by gaining electrons.
• The outermost shell of non-metals contains 4 to 8 electrons.
• The exceptional cases are Hydrogen and Helium, which have one and two electrons respectively in their outermost shell.
• Hydrogen contains one electron in its K shell and shows non-metallic characteristics.
• Hydrogen is present in the form of gas and chemically represented as ${}_1{}^1\mathrm{H}$.

Therefore, Hydrogen is a non-metal that has only one electron in its outermost shell.