Answer:
D has 18 electrons (since atomic number = protons = electrons)
- [Ne]3s² 3p⁶ (spdf electron configuration)
- 2, 8, 8 (basic electron configuration)
E has 20 electrons
- [Ar]4s² (spdf electron configuration)
- 2, 8, 8, 2 (basic electron configuration)
Explanation:
In spdf form, we are basically spreading out the total number of electrons over the different spdf orbitals. While doing this we have to remember that an s-orbital holds 2 electrons max, a p-orbital holds 6 electrons max, a d-orbital holds 10 electrons max, and an f-orbital holds 14 electrons max.
Based on energy levels, the orbitals are filled in the following order:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, and 7p
So for example Argon with 18 electrons would be filled in the following way:
1s², 2s², 2p⁶, 3s², 3p⁶.
This can be abbreviated using the configuration of the previous Noble gas for example [Ne] = 1s², 2s², 2p⁶
∴ we can express Argon as [Ne] 3s², 3p⁶.
