MOLECULE : -
A molecule is the smallest particle of a substance of independent existence. A molecule is composed of two or more atoms, its constituent atoms are chemically bonded together.
MOLECULAR FORMULA : -
The actual number of the constituent atoms in a molecule of a substance is called its molecular formula.
CLASSIFACTION OF MOLECULES : -
The atoms bonded together in a molecule may be of the same type or of different types.
1. Molecules of elements
2. Molecules of compounds
MOLECULES OF ELEMENTS : -
A molecule of an element is composed of two or more than two similar type of atoms.
ATOMICITY : -
The number of atoms bonded in a molecule of an element is called its atomicity.
CLASSIFICATION OF MOLECULES OF ELEMENTS BY ATOMICITY : -
The number of atoms in a molecule the elements are classified as monatomic, diatomic, diatomic and polyatomic.
MONATOMIC MOLECULES OF ELEMENTS : -
The noble gases exist in the atomic form and are stable, it’s called monatomic molecules.
EXAMPLE : -
Helium (He),
Neon (Ne),
Argon (Ar),
krypton (Kr),
Xenon (Xe),
Radon (Rn)
DIATOMIC MOLECULES OF ELEMENTS : -
A molecule containing two atoms is called a diatomic molecule. The atomicity of each diatomic molecule is 2.
EXAMPLE : -
Hydrogen (H2),
Oxygen (O2),
Nitrogen (N2),
Fluorine (F2),
Chlorine (Cl2),
Bromine (Br2)
TRIATOMIC MOLECULES OF ELEMENTS : -
A molecule containing three atoms is called a triatomic molecule.
EXAMPLE : -
Ozone (O3)
POLYATOMIC MOLECULES OF ELEMENTS : -
The molecules containing four or more atoms of the same element are called polyatomic molecules.
EXAMPLE : -
Phosphorus (P4)
Sulphur (S8)
Boron (B12)
Fullerene (C60)
MOLECULES OF COMPOUNDS : -
A molecule of compound is composed of two or more atoms of different elements in definite proportions and chemically bonded.
| COMPOUND |
FORMULA |
TYPE |
ATOMICITY |
| Hydrogen chloride |
HCl |
Diatomic |
2 |
| Carbon dioxide |
CO2 |
Triatomic |
3 |
| Ammonia |
NH3 |
Tetratomic |
4 |
| Methane |
CH4 |
Pentatonic |
5 |
| Methanol |
H3OH |
Hex atomic |
6 |
