Answer/Explanation:
No compounds must be made up of two or more elements. otherwise it wouldn't be a compound. There must be some type of combination or it isn't a compound.
One characteristic of a lagoon is often: concentrated salt.
As you go across a period, radius shrinks because you are adding protons. The added positive charge increases pull on the electron shells.
As you go down a group, radius gets larger because you are increasing shells of electrons. This increases shielding of the nucleus' positive charge, so the electrons are not pulled in as much.
