Answer:
C.Lithium
D.Potassium
Explanation:
All elements of group 1 have the oxidation number equal to 1. The elements of group 1 in the options given in the question are Potassium and Lithium.
The oxidation number of an element in any chemical species is the charge that would remain on the atom of that element if the electrons in each bond formed by that atom were attributed to the most electronegative atom.
When an element can have several oxidation numbers (depending on the chemical species to which it belongs) it is said to be in different oxidation states. In some polyatomic chemical species, an element may have atoms with different oxidation numbers due to asymmetric distributions of electrons in such cases, it is usual to consider the “average oxidation number”.
