What is the relative formula mass of a compound?

How are isotopes of the same chemical element alike? how are they different?

Achemical equilibrium between gaseous reactants and products is shown. n2(g) + 3h2(g) ⇌ 2nh3(g) how will the reaction be affected if the pressure on the system is increased? it will shift toward the reactant side as there is lower pressure on the reactant side. it will shift toward the product side as there is higher pressure on the product side. it will shift toward the reactant side as there are a greater number of moles of gas on the reactant side. it will shift toward the product side as there are a fewer number of moles of gas on the product side.

Why do electrons further from the nucleus have more energy