Question

What is ionization energy?

Answer 1

Ionization energy is the minimum energy required to remove the most loosely bound electron from a neutral gaseous atom in its ground state.

\[\ce{M(g) + IE → M^+ (g) + e ¯ }\]

Trends in Periodic Table:

• Increases across a period (left to right).
• Decreases down a group (top to bottom).

Factors Affecting Ionization Energy:

• Atomic Size (Larger size → Lower IE)
• Nuclear Charge (Higher charge → Higher IE)
• Electron Shielding Effect (More shielding → Lower IE)