How many p orbitals are occupied by electrons in a krypton (Kr) atom in its ground state?

• A. 6
• B. 12
• C. 9
• D. 3

Answer: (C)

Verified step by step guidance

1. Recall that each p subshell contains 3 p orbitals, and each orbital can hold up to 2 electrons.
2. Determine the electron configuration of krypton (Kr), which has 36 electrons, to identify how many electrons occupy the p orbitals.
3. Write the electron configuration: \$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6$.
4. Count the p orbitals that contain electrons: the 2p, 3p, and 4p subshells are fully occupied, each with 3 orbitals filled.
5. Since each of these three p subshells has 3 orbitals occupied, the total number of occupied p orbitals is \$3 \times 3 = 9$.