Question

1. complete the electron configuration for the following element: d. magnesium ar3d^{10}4s^{2}4p^{4}

Explanation:

Step1: Recall magnesium's atomic number

Magnesium has an atomic number of 12.

Step2: Write electron - configuration rules

Electrons fill orbitals in order of increasing energy: 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p etc.

Step3: Fill the orbitals

1s can hold 2 electrons, 2s can hold 2 electrons, 2p can hold 6 electrons, and 3s can hold 2 electrons. For magnesium (Z = 12), the electron - configuration is 1s²2s²2p⁶3s². In noble - gas core notation, neon (Ne) has an atomic number of 10 with electron - configuration 1s²2s²2p⁶. So, magnesium's electron - configuration in noble - gas core notation is [Ne]3s². The given [Ar]3d¹⁰4s²4p⁴ is incorrect for magnesium.

Answer:

[Ne]3s²