What are Molecules?
A Molecule can be defined as a group of atoms bonded chemically with attractive forces. It is a unit formed of two or more atoms and can exist freely in nature. It is the smallest unit having an independent existence.
Molecules in elements and compounds
Atoms form molecules, and molecules make up elements and compounds. You can tell whether molecules will have atoms of the same kind or different kind, by checking whether the molecule belongs to an element or a compound.
Molecules in elements and compounds
Let us first look at molecules in elements
What is Atomicity of a molecule?
The number of atoms in a molecule is called the Atomicity of the molecule.
Based on the atomicity of their molecules, elements can be monoatomic, diatomic or triatomic.
● Monoatomic state
Atoms of some elements exist singly without forming a chemical bond. Such a case is called the Monoatomic state.
Examples of monoatomic elements include helium, argon, neon, etc.
● Diatomic state
Two similar atoms come together to form a Diatomic molecule.
For example, in hydrogen, 2 atoms exist in one molecule. Oxygen also exists in diatomic state as 𝑂2.
● Triatomic state
When 3 similar atoms form a molecule, it is known as Triatomic.
For example, 3 atoms of oxygen combine to give a single ozone molecule.
Like elements, compounds also have atomicity. We will learn about it in the next segment.