Question

Element X has electronic configuration 2, 8, 18, 8, 1.
Without identifying X,​

Answer 1

Electronic configuration of X = 2,8,18,8,1

Atomic number = 37

So element is Rubidium

Answer 2

I believe your question is: The element X has the electronic configuration 2, 8, 18, 8, 1. Without identifying x,

a)predict the sign and charge on a single ion or X.

b)write if X be an oxidizing agent or reducing agent and why.

Answer:

a)X has one electron in its valence shell and to achieve a full octet, X loses an electron to form a cation.  The ion has a positive sign and charge of +1.

b)Element X loses an electron and is an electropositive element and thus is oxidised in a redox reaction.  So, it acts as a reducing agent.