1. Ionization energy is the minimum energy required to remove the most loosely bound electron from a neutral atom in the gaseous state.
2.
a) Ionization energy generally increases across a period. This is because the number of protons (nuclear charge) increases, pulling electrons closer and making them harder to remove, while electrons are added to the same principal energy level, resulting in minimal increase in shielding.
b) Ionization energy generally decreases down a group. This is because each successive element has electrons in higher principal energy levels (farther from the nucleus), and the increased number of inner electron shells provides more shielding, reducing the effective nuclear charge felt by the outermost electrons.
3. Factors influencing the ease of removing an electron include:
- Nuclear charge (number of protons)
- Distance of the electron from the nucleus (principal quantum number)
- Shielding effect of inner electrons
- Electron-electron repulsion (especially in half-filled or fully filled subshells)
4. P (3p)
5.
a) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵ → i) 1356 kJ/mol
b) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² → iii) 409 kJ/mol
c) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ → ii) 595 kJ/mol
6. Li
7.
740 → Na
578 → K
786 → Mg
1012 → Al
999 → Si
8.
a) Carbon
b) Calcium
c) Helium
d) Argon
Parent Tip: Review the logic above to help your child master the concept of ionization energy worksheet.
