What is the Atomic Size Trend in the Periodic Table?
Answer – An atom’s size decreases gradually across a period and increases down a group in the periodic table.
Explanation:
The decrease in an atom’s size across the periodic table is primarily due to an increase in the effective nuclear charge. The increasing number of protons in the nucleus exerts a stronger attractive force on the electrons, pulling them closer to the nucleus and, thus, reducing the atomic radius. Therefore, there is a decrease in the atom’s size on moving from left to right in the periodic table.
However, as one moves down a group (top to bottom) in the periodic table, the atomic size increases. This is because of the addition of new energy levels of electrons. The increase in the number of electron shells outweighs the increase in the number of protons, resulting in a larger atomic radius.
