Question

Assertion: Alkali metals are reducing agents, while halogens [non-metals], are strong oxidizing agents.

Reason: Metals have 1,2 or 3 valence electrons so they always ionize by losing electrons while nonmetals have 4,5,6 or 7 valence electrons so they ionize by gaining electrons.

A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both assertion and Reason are incorrect.

Answer 1

We know that, the elements present in group 1 of the periodic table such as lithium, sodium, potassium etc. are termed as alkali metals and the elements that are present in group 17 of the periodic table, such as chlorine, bromine, iodine etc. are termed as halogens.

Complete step by step answer:
Let’s first understand oxidizing and reducing agents in detail. A reducing agent is an element or compound that can donate electrons and an oxidizing agent is an element or compound that can accept electrons.

Here, given that alkali metals are reducing agents and halogens are oxidizing agents. Let’s understand if the given statement is correct or not.

Let’s take an alkali metal, namely sodium (Na). The atomic number of sodium is 11, So, its electronic configuration is 2,8,1. There is only one valence electron. So, sodium can donate this electron easily to achieve stable configuration.

${\rm{Na}} - {e^ - } \to {\rm{N}}{{\rm{a}}^ + }$

and we know a reducing agent can donate electrons. So, alkali metals are reducing agents.

Therefore, we can say that metals have 1,2 or 3 valence electrons so they always ionize by losing electrons.

Also given that halogens are oxidizing agents. Let’s take a halogen, namely fluorine. The atomic number of fluorine is 9. So, its electronic configuration is 2,7. Here, only one electron is needed by fluorine to obtain stable electronic configuration.

${\rm{F}} + {e^ - } \to {{\rm{F}}^ - }$

So, a halogen gains electrons to achieve an octet. Hence, halogens are oxidizing agents.

Therefore, we can say that all non-metals have 4,5,6 or 7 valence electrons so they ionize by gaining electrons.

Hence, the correct choice is option A.

Note:
Always remember that oxidation is the process in which loss of electrons occurs and reduction is the process in which gaining of electrons occur. So, we can say that a reducing agent undergoes oxidation and an oxidizing agent undergoes reduction.