Question

22 apply concepts use the concepts of energy and stability as they relate to orbital filling to write the electron configuration for iron.

Explanation:

Step1: Determine atomic number of iron

Iron (Fe) has an atomic number of 26, so it has 26 electrons.

Step2: Fill orbitals according to Aufbau principle

Electrons fill orbitals in order of increasing energy. The order is 1s < 2s < 2p < 3s < 3p < 4s < 3d.
1s can hold 2 electrons, 2s can hold 2 electrons, 2p can hold 6 electrons, 3s can hold 2 electrons, 3p can hold 6 electrons, 4s can hold 2 electrons and then we start filling 3d.

Step3: Calculate electrons in each orbital

1s²: 2 electrons.
2s²: 2 electrons.
2p⁶: 6 electrons.
3s²: 2 electrons.
3p⁶: 6 electrons.
4s²: 2 electrons.
3d⁶: 6 electrons (2 + 2+6 + 2+6 + 2+6=26).

Answer:

1s²2s²2p⁶3s²3p⁶4s²3d⁶