Covalent radius

Covalent radius

Definition:

• The covalent radius is a measure of the size of individual atoms. It represents the distance from the nucleus to the outermost electron in an atom.

Trends in Covalent Radius:

• The covalent radius exhibits distinct trends as you move across a period (from left to right) and down a group (from top to bottom) in the periodic table.

Across a Period (Left to Right):

• The covalent radius decreases as you move from left to right across a period.
• Explanation: Atoms in a period have more electrons in their outermost energy level and more protons in their nucleus. The increased nuclear charge exerts a stronger attraction on the electrons, pulling them closer together and resulting in a smaller covalent radius.

Down a Group (Top to Bottom):

• The covalent radius increases as you move down a group in the periodic table.
• Explanation: The covalent radius increases because of the shielding effect of the filled inner electron levels. These inner electrons act as a screen or shield, reducing the effective nuclear charge felt by the outer electrons, allowing them to occupy larger orbital regions.