Question

conceptual checkpoint 9.6 - enhanced - with feedback
part a
which pair of elements has the same total number of electrons in its p orbitals?
ar and ca
p and n
na and k
k and kr

Explanation:

Step1: Write electron configurations

• For Ar (Atomic number = 18):
• Electron configuration: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\).
• Number of \(p\) - electrons: \(2p^{6}+3p^{6}=12\).
• For Ca (Atomic number = 20):
• Electron configuration: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\).
• Number of \(p\) - electrons: \(2p^{6}+3p^{6}=12\).
• For P (Atomic number = 15):
• Electron configuration: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}\).
• Number of \(p\) - electrons: \(2p^{6}+3p^{3}=9\).
• For N (Atomic number = 7):
• Electron configuration: \(1s^{2}2s^{2}2p^{3}\).
• Number of \(p\) - electrons: \(2p^{3}=3\).
• For Na (Atomic number = 11):
• Electron configuration: \(1s^{2}2s^{2}2p^{6}3s^{1}\).
• Number of \(p\) - electrons: \(2p^{6}=6\).
• For K (Atomic number = 19):
• Electron configuration: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}\).
• Number of \(p\) - electrons: \(2p^{6}+3p^{6}=12\).
• For Kr (Atomic number = 36):
• Electron configuration: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}\).
• Number of \(p\) - electrons: \(2p^{6}+3p^{6}+4p^{6}=18\).

Answer:

Ar and Ca