Question

Predict the position of the elements which form the largest cation and the smallest anion in the modern periodic table.

Answer 1

• The positively charged ions are known as cations while negatively charged ions are known as anions.
• Cations are smaller than the corresponding atoms because of the increase in effective nuclear charge while anions are greater than the corresponding atoms because of a decrease in effective nuclear charge.
• As we know that atomic size increases on moving top to bottom in a group and decreases on moving left to right in a period.
• Hence, the largest known element should be Cesium (Cs). Hence, the largest cation will be ${\mathrm{Cs}}^{+}$.
• Hence, the smallest known element should be Fluorine (F). Hence, the smallest anion will be ${\mathrm{F}}^{-}$.