Aneyanjuu

What is a Molecule?
A molecule is defined as the smallest unit of a compound that contains the chemical properties of the compound. Molecules are made up of groups of atoms. Describing the structure of an atom, an atom is also sub-divided into smaller units. Protons, electrons, and neutrons are sub-particles of an atom. The protons and neutrons are contained inside the nucleus of the atom and electrons revolve around the nucleus.

Protons are positively charged particles whereas electrons are negatively charged particles. Neutrons do not carry any charge. So we can say that the nucleus is positively charged due to the presence of protons. The nucleus is a bulk mass at the centre of an atom. Atoms are largely vacant.

Every element has a certain atomic number. The atomic number of an element is defined as the number of protons present in its nucleus. It is denoted by Z.

When we talk about the mass of atoms, the mass of its particles is taken into consideration. Electrons have negligible mass. Hence the mass of an atom is the sum of the mass of protons and neutrons. The mass number is denoted by A.