If the electronic configuration of an element is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s², the four electrons involved in chemical bond formation will be_____.

(i) 3p⁶

(ii) 3p⁶, 4s²

(iii) 3p⁶, 3d²

(iv) 3d², 4s²

He₂ has zero bond order hence it does not exist.

The three fundamental laws of chemistry are - Law of Definite Proportions, Law of Conservation of Mass, and Law of Multiple Proportions.

The three types of chemical bonds are - ionic, metallic and covalent bonds. When the electrons transfer between the atoms, they form the Ionic bonds by producing charged ions that are attracted to each other. When atoms share electrons, covalent bonds are created. When metal atoms share a sea of delocalized electrons, metallic bonds get created.