How many unpaired electrons are in a ground state Magnesium atom? 0 2 6 4
The Correct Answer and Explanation is:
The correct answer is 0.
Here’s why:
A ground state magnesium atom has an atomic number of 12, meaning it has 12 electrons. The electron configuration for magnesium (Mg) is:
1s2 2s2 2p6 3s21s^2 \, 2s^2 \, 2p^6 \, 3s^21s22s22p63s2
This configuration can be explained as follows:
- The first energy level (1s) holds 2 electrons.
- The second energy level (2s and 2p) holds 8 electrons (2 in the 2s orbital and 6 in the 2p orbitals).
- The third energy level (3s) holds 2 electrons.
In the ground state, electrons fill orbitals in the order of increasing energy, and each orbital can hold a maximum of two electrons with opposite spins.
- The 1s and 2s orbitals are fully filled, and the 2p orbital is also fully filled with 6 electrons.
- The 3s orbital is fully filled with 2 electrons.
Since all the orbitals in the ground state are completely filled, there are no unpaired electrons.
Unpaired electrons occur when an orbital contains just one electron, but in magnesium’s ground state, all orbitals are paired. Therefore, magnesium has 0 unpaired electrons in its ground state.
