1. Se considera elementele: Na, I,Al, Br, O,Ca. Alege elemental cu raza atomic cea mai mare. Alege elemental cu caracterul electronegative cel mai pronuntat. Aranjeaza elementele in ordinea descrescatoare a caracterului metallic

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

it is stable as it is in group 0 which have full outer shells of electrons