What change in energy takes place when a molecule is formed from its atoms ?

Giving two examples of compounds having covalent bonds. Explain their properties.

Draw diagram showing structure of hydrogen molecule.

Hydrogen atoms are held together to form hydrogen molecule by

Explain the formation of the hydrogen molecules with a diagram.

$\mathrm{M}\mathrm{Y}$ and ${\mathrm{N}\mathrm{Y}}_3$ are two nearly insoluble salts, have the same ${\mathrm{K}}_{\mathrm{S}\mathrm{P}}$ values of $6.2\times$ $10^{-13}$ at room temperature. Which statement would  be true in regard to MY and NY${}_3?$ 

Hydrogen atoms, in a $H_2$ molecule _______ their electrons.

Which of the following compounds are covalent?

Diatomic molecule has a dipole moment of $1.2D$ If its bond $1.0\mathring{A}$ what fraction of an electronic charge exists on each atom ? .

Which of the following has a $3$ centred $2$ electron bond?