Question

how the molecules formed?

Answer 1

Each molecule consists of one or several atoms. The molecules are formed via bonds between its atoms : covalent, ionic, van-der-Waals, hydrogen, hydrophobic interactions. Generally molecule is considered to have ionic bond if the electronegativity difference between its atoms is greater or equal 1.9 (Pauling scale). And if it's less then it's covalent bond.&