Which of the following is true of a neutral halogen?
Its electron configuration ends with
It has an unpaired electron in one of its orbitals
It has lower affinity for electrons than the alkali metal in its period
It has more valence electrons than the noble gas in its period
An element from which of the following groups is most likely to react with a halogen?
Alkaline earth metals
Halogens
Alkali metals
Noble gases