Answer:
9,000, 100 has 7 significant figures
Explanation:
S- and P-Block elements are known as Representative elements.
Groups 1-2 and Groups 13-18
A layer of hot liquid rock
H2se is a ionic bond which requires higher energy to change into a gas, while h2s is a covalent bond requiring less energy
Answer: 
Explanation: A double displacement reaction is one in which exchange of ions take place.
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.
