The electron configuration of a ground-state Titanium atom (Ti) is: 1s2 2s2 2p6 3s2 3p6 4s2 3d2
The Correct Answer and Explanation is:
The correct electron configuration of a ground-state titanium (Ti) atom is:
Ar\text{Ar}Ar 4s² 3d²
Explanation:
Titanium (Ti) has an atomic number of 22, which means it has 22 electrons in its neutral ground state.
To write its electron configuration, we fill the orbitals in the order of increasing energy using the Aufbau principle, which follows this general order:
1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p, and so on.
Filling the first 18 electrons gives us the electron configuration of Argon (Ar):
Ar\text{Ar}Ar = 1s² 2s² 2p⁶ 3s² 3p⁶
Total = 18 electrons.
After Argon, the next electrons go into:
- 4s orbital: 2 electrons → 4s²
- 3d orbital: 2 electrons → 3d²
So, the full configuration for Titanium is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d², or using noble gas shorthand:
Ar\text{Ar}Ar 4s² 3d²
This is the ground-state configuration, where electrons occupy the lowest energy orbitals available. The 4s orbital is filled before 3d because it is lower in energy when empty or half-filled. Later in chemical bonding, this order can sometimes shift, but for the isolated atom in its ground state, this is the correct arrangement.
Let’s now eliminate the incorrect choices:
- ArArAr 3d⁴: Incorrect, only 2 electrons are in the 3d orbital.
- ArArAr 4s² 3d²: ✔️ Correct.
- ArArAr 4s² 4p²: Incorrect, 4p comes after 3d and would not be occupied at this stage.
- ArArAr 4s² 4d²: Incorrect, 4d orbitals are much higher in energy and are not filled for Ti.
✅ Correct answer: ArArAr 4s² 3d²
