For the element titanium (Ti), which has the electron configuration [Ar] 4s^2 3d^2, how many unpaired electrons are present in a neutral Ti atom?

• A. 2
• B. 1
• C. 0
• D. 4

Answer: (A)

Verified step by step guidance

1. Identify the electron configuration of titanium (Ti) given as [Ar] 4s^2 3d^2. This means the electrons beyond the argon core are 2 electrons in the 4s orbital and 2 electrons in the 3d orbitals.
2. Recall that the 4s orbital can hold up to 2 electrons and is filled before the 3d orbitals. Since 4s^2 is fully paired, these 2 electrons do not contribute to unpaired electrons.
3. Focus on the 3d^2 configuration. The 3d subshell has 5 orbitals, each capable of holding 2 electrons with opposite spins.
4. Apply Hund's rule, which states that electrons will fill empty orbitals singly with parallel spins before pairing up. Therefore, the 2 electrons in 3d will occupy two separate orbitals, each unpaired.
5. Conclude that the number of unpaired electrons in a neutral Ti atom is equal to the number of singly occupied 3d orbitals, which is 2.