Explain why chlorine (Cl2) is a gas at room temperature, but sodium chloride (NaCl) is a solid at room
temperature.
Include description of the bonding and structure of chloride and sodium chloride in your answer

The melting/boiling point of a substance determines what state of matter it takes at a certain temperature.

In Cl2 there are covalent bonds between the atoms forming simple molecules. There are weak attractions between molecules of Cl2 meaning little energy is needed to break these forces of attraction and therefore Cl2 has a low boiling point.

NaCl on the other hand has strong electrostatic forces of attraction between the positvely charged Na ion and the negatively charged Cl ion. NaCl forms a giant ionic lattice that requires high amounts of energy to break and therefore has a high melting point.

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.