Answer:
+1, lose, 1, 4s, 4s and 3d
Explanation:
An element with the valence electron configuration 4s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose 1 electron from the 4s subshell.
The corresponding oxidation reaction is:
K ⇒ K¹⁺ + 1 e⁻
[Ar] 4s¹ ⇒ [Ar]
If an element with the valence configuration 4s² 3d⁶ loses 3 electrons, these electrons would be removed from the 4s and 3d subshell(s).
The corresponding oxidation reaction is:
Fe ⇒ Fe³⁺ + 3 e⁻
[Ar] 4s² 3d⁶ ⇒ [Ar] 4s⁰ 3d⁵
