Question

which family contains elements that exist as two gases, one liquid (br), and two solids?
options: halogens, noble gases, oxygen family, nitrogen family

which family of elements has exactly one valence electron and is highly reactive with water?
options: noble gases, halogens, alkali metals, alkaline earth metals

what is unique about mercury (hg) among the transition metals?
options: it’s the most reactive, it’s a liquid at room temperature, it doesn’t conduct electricity, it’s a nonmetal

Explanation:

First Question (Which family contains elements that exist as two gases, one liquid (Br), and two solids?):

Halogens include fluorine (gas), chlorine (gas), bromine (liquid), iodine (solid), and astatine (solid). So the Halogens family matches this description.

Alkali Metals (Group 1) have one valence electron and are highly reactive with water (e.g., Na, K react vigorously with water). Noble Gases are inert, Halogens have 7 valence electrons, Alkaline Earth Metals have 2 valence electrons. So Alkali Metals is the answer.

Most transition metals are solids at room temperature, but mercury is a liquid at room temperature. The other options: it is a metal (conducts electricity), and is not the most reactive transition metal, nor a non - metal.

Answer:

Halogens

Second Question (Which family of elements has exactly one valence electron and is highly reactive with water?):