Write the electron configuration of an ion of Na +1

Na⁺ - 1s²2s²2p⁶

Explanation:

Step 1: Find electron configuration of neutral atom Na

Na - 1s²2s²2p⁶3s¹

(Sodium is in the 3rd period group 1, so it's neutral atom will have an electron in the 3s sublevel)

Step 2: Find electron configuration of Na⁺ ion

From Na to Na⁺, we will have to remove an electron.

Because the higher the quantum numbers, the energy will increase. Since atoms want to be the lowest energy state possible, it will want to remove as much energy as possible. Since the 3s e⁻ is the highest energy e⁻, it will remove that e⁻

So, Na - 1s²2s²2p⁶3s¹ → Na⁺ - 1s²2s²2p⁶

We see here that Na⁺ would have the same electron configuration as Ne and it's valence electrons maxed.