How many valence electrons are present in the ground-state electron configuration of a nitrogen atom?

• A. 2
• B. 7
• C. 5
• D. 3

Answer: (C)

Verified step by step guidance

1. Identify the atomic number of nitrogen, which is 7. This means a nitrogen atom has 7 electrons in total.
2. Write the ground-state electron configuration of nitrogen by filling the orbitals in order of increasing energy: 1s, 2s, 2p, etc. For nitrogen, the configuration is \$1s^2 2s^2 2p^3$.
3. Determine which electrons are valence electrons. Valence electrons are those in the outermost shell (highest principal quantum number). For nitrogen, the outermost shell is the second shell (n=2).
4. Count the electrons in the 2s and 2p orbitals: \$2s^2\( means 2 electrons, and \)2p^3$ means 3 electrons, so total valence electrons = 2 + 3.
5. Conclude that the number of valence electrons in nitrogen is the sum of electrons in the 2s and 2p orbitals.