Answer:

Question 4 :-

What is a chemical equation ?

=> A chemical equation represents the reaction of Given group of atoms or single atom .

What is the meaning of the term reactants ?

=> The reactants combines in a given reaction to form another chemicals .

Now , What is meant by products ?

=> In a given chemical reaction the chemicals / Materials formed by the reaction of reactants are known as products .

Note :- The reactants or the products can either be single or more than single .

How to find what is/are reactants and are/is products ?

=> In a chemical equation , when we write a equation we write a arrow symbol to represent the products . On which side the head of the arrow is the side of the products .

Question 2 :-

What is meant by the term "Valency" ?

=> The no. of electrons present in the outermost shell of a given atom is known as it's valency .

For Example :- Let us consider an atom "Z" with no. of electrons in outermost shell = x

Then , You have to note that ,

If x < 5 , then the valency of Z is x .

x > 5 , then the valency of Z is 8 - x . Because we have to fill the octate .

Question 3 :-

What is variable Valency ?

=> The property of an element to What is meant by the term "Symbol" ?

=> In chemistry , Symbol is the term by which we can represent a given element in written . Note that , symbols are very important to write a chemical equation .

For Example :- Symbol of Silver and Gold are Ag and Au respectively .