Question

2nd period electron affinity order

Answer 1

Electron affinity increases in the order: Ne < N < Be < Li < B < C < O < F.

Answer 2

For the second period elements (Li, Be, B, C, N, O, F, Ne), the general trend is an increase in electron affinity from left to right. However, due to electron configuration stability, there are exceptions:

• Be (1s² 2s²): A fully filled s orbital makes it hard to add an extra electron.
• N (1s² 2s² 2p³): A half-filled p subshell is relatively stable.
• Ne (1s² 2s² 2p⁶): With a completely filled p orbital, it resists gaining an electron.

Thus, taking these exceptions into account, the increasing order of electron affinity is:

$$\mathrm{Ne} < \mathrm{N} < \mathrm{Be} < \mathrm{Li} < \mathrm{B} < \mathrm{C} < \mathrm{O} < \mathrm{F}$$