Valence Electron Chemistry Example 1

Solution

1. 1
   Nitrogen has atomic number 7, so it has 7 electrons. Write the electron configuration by filling subshells in order of energy.
2. 2
   Electron configuration: $1s^2\,2s^2\,2p^3$. Verify: $2 + 2 + 3 = 7$ electrons total.
3. 3
   Identify valence electrons as those in the outermost shell ($n = 2$): $2s^2$ and $2p^3$ contribute $2 + 3 = 5$ valence electrons.