Answer:
Period
Explanation:
horizontal is a period and verticle is a group
The law of conservation of mass dictates that the total mass of reactants must be equal to the total mass of the products. Thus:
mass(MgO) = mass(Mg) + mass(O)
mass(MgO) = 24 + 16
mass(MgO) = 40 g
The third option is correct.
The definition of a common ion as it applies to Le Chatelier's principle is an ion that is present in an equilibrium system and a compound added to the system. This is the case since in Le Chatelier's principle, it is based on an equilibrium system and where the reaction shifts to the left or to the right; towards the products or the reactants side.