Which one of the following statements is correct?
a. an electron has a negative electrical charge.
b. an electron has a neutral electrical charge.
c. an electron is much larger than an atom.
d. an electron is located inside the nucleus of an atom.

Option (A) is the correct answer.

Explanation:

An atom consists of three sub atomic particles. These particles are protons, electrons and neutrons.

Protons have a positive charge. Whereas neutrons have no charge. On the other hand, electrons have a negative charge.

Thus, we can conclude that out of the given options, an electron has a negative electrical charge is the correct statement.

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.