Group 7 elements react by gaining an electron in their outer shell. Why does their reactivity decrease as you go down the group?The outer shell becomes further away from the nucleus, so it is easier to gain an electronThe outer shell becomes closer to the nucleus, so it is harder to gain an electronThe outer shell becomes further away from the nucleus, so it is harder to gain an electronThe outer shell becomes closer to the nucleus, so it is easier to gain an electron2Which halogen is a liquid at room temperature?BromineChlorineIodineFluorine3The halogens exist as:Positive ionsNegative ionsMolecules made of pairs of atoms joined by a covalent bondMolecules made of pairs of atoms joined by an ionic bond4A chemical reaction in which a more reactive element takes the compound away from a less reactive element is known as:CombustionReductionDisplacementOxidation5What will happen when chlorine solution is added to sodium iodide solution?Iodine is producedChlorine gas is producedAn explosionNo reaction6Which of the following is a balanced symbol equation for the reaction of chlorine solution with sodium bromide solution?Cl + NaBr → NaCl + BrCl2 + NaBr → NaCl + Br22Cl + 2NaBr → 2NaCl + 2BrCl2 + 2NaBr → 2NaCl + Br2