How many d electrons are present in a ground-state Mn atom?

• A. 3
• B. 5
• C. 7
• D. 0

Answer: (B)

Verified step by step guidance

1. Identify the atomic number of manganese (Mn), which tells you the total number of electrons in a neutral atom. Manganese has an atomic number of 25.
2. Write the electron configuration for Mn in its ground state by filling orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p, 4s, then 3d.
3. Recall that the 3d subshell can hold up to 10 electrons, and the 4s subshell fills before the 3d subshell for transition metals like Mn.
4. Determine how many electrons occupy the 3d subshell by counting the electrons assigned to 3d orbitals in the electron configuration of Mn.
5. The number of electrons in the 3d subshell corresponds to the number of d electrons in the ground-state Mn atom.