Answer: 
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here iron is having an oxidation state of +3 called as 
cation and oxide 
is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral 
.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
A conductor is what helps heat or electricity pass through an object. Examples of conductors are, silver, iron, aluminum, etc..
An insulator does the opposite and instead, stops either from going through. Examples of an insulator is paper, wood, rubber, etc.
Noble Gas. Metals have 1 or 2 Valence Electrons. Halogens have 7 Valence Electrons. Semi-Metals can have different amounts.
Answer:
C
Explanation
On the reactants side there is 4 Hydrogen atoms in total and two oxygen atoms on the left however on the right there is two hydrogen atoms and one oxygen atom. Leaving this equation unbalanced
Answer: C) Subatomic particles
Explanation: I just learned this in ap environmental science
