Question

write down classification of molecule

Answer 1

Molecules can be classified in two ways: 1) based on their composition, 2) according to their chemical bonds.

Explanation:

• A molecule is two or more atoms bonded together to form a single chemical entity.

• When two atoms share an electron, or multiple electrons, a strong bond is formed between them as the electron passes from one nucleus to the other and back. This electron activity ties the two atoms together.

• Molecules can form single bond, double bonds, triple bonds, and even more, depending on how many electrons they are sharing.

• A molecule is defined as an electrically neutral group of two or more atoms connected by chemical bonds.

Classification based on composition:

1. Diatomic molecule -  A diatomic atom is composed of only two atoms, of the same or different chemical elements. These may be atoms of single element i.e. homonuclear or atoms of different elements i.e. heteronuclear. $O_{2}$ is a homonuclear molecule and HCl is a heteronuclear molecule.
2. Polyatomic molecule – A polyatomic molecule consists of more than two atoms. Ex: $H_{2} O$
3. Macromolecule – A macromolecule is a very large molecule, often consisting of sub units. Proteins and DNA are examples of macromolecules.

Classification based on type of chemical bonding:

1. Covalent molecule – Covalent molecules consist of atoms connected by covalent chemical bonds. Ex: HCl
2. Ionic molecule -- Ionic molecules consist of both metals and nonmetals. Ex: NaCl

Answer 2

A molecule can be defined as an electrically neutral group of two or more atoms that are bonded by a chemical bond.

Explanations:

The molecules are classified into two types. They are:

Monatomic molecules:

• If a single atom exists on its own (which is rare), it is called a single atom. In other words, the elements are in a pure and peculiar form.  

• However, the only practical example that can fall into this category is a noble gas that itself exists as an atom because it has an outer shell with a full electron octet.  

• Therefore, they try not to take in or give up electrons for more stability.  

• Therefore, noble gases are stable in the form of single atoms.  Examples:  He – Helium, Ne – Neon, Ar – Argon, Xe – Xenon, Kr – Krypton, Rn – Radon.

Diatomic molecules:

• When two atoms are connected to each other, they are called diatomic atoms.  

• These atoms can be the same or different.  

• When they are composed of two similar atoms bonded to each other, they are called "isonuclear diatoms", and when they are composed of different types, they are called "heteronuclear diatoms".  Examples: CO, NO, HCl etc