Define symbole and valeny.

Chemical symbol

This is used to identify an element without having to write the full name and as such is a designation for the element. It is used in chemical reactions and is usually either one or two letters. Some symbols are, Iron - Fe, Hydrogen - H and Oxygen - O.

Valency

This refers to the capacity of an element to combine with another to form a compound. It is measured by the number of electrons that an atom of an element gains, looses or shares when a chemical reaction involving it takes place.

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.

answersilicon (si); oxygen (o);