What is the value of electron gain enthalpy of Na+ if IE1 of Na = 5.1 eV?
- -5.1 eV
- -10.2 eV
- +2.55 eV
- +10.2 eV
Answer
(1) -5.1 eV
Solution
Na(g) Na+(g) + e- ; IE1 = +5.1 eV (energy absorbed)
Electron gain by Na+ is the reverse process:
Na+(g) + e- Na(g)
⇒ The same energy is released, so egH(Na+) = -IE1(Na) = -5.1 eV
Answer: (1)