CHEMISTRY CH11 Atomic Structure — Science STD 9 — Question

Hydrogen is the lightest, smallest and first element of the periodic table. Its electronic configuration (1s¹) is the simplest of all the elements. It occupies a unique position in the periodic table. It behaves like alkali metals as well as halogens in its properties. In the periodic table, it is placed at the top of the alkali metals.

• Hydrogen can lose its one electron to form a hydrogen ion (H⁺) like alkali metals.
• It can also gain one electron to form the hydride ion (H^–) like halogens.
• Alkali metals are solids while hydrogen is a gas.
  Hence the position of hydrogen in the modem periodic table is still under debate
  as the properties of hydrogen are unique.