Question

only metal that is liquid at room temperature
only nonmetal that is liquid at room temperature
solid halogen with the smallest atomic mass
gas member of group 15
gas member of group 16
gas member of group 1
alkali metal with the smallest atomic mass
gas member of group 18 with the least number of electron energy levels
solid member of the nitrogen group that has the smallest atomic mass
solid member of the oxygen group that has the smallest atomic mass
mercury bromine iodine nitrogen oxygen hydrogen lithium helium phosphorus sulfur

Explanation:

Step1: Analyze each term

• Only metal liquid at room temp: Mercury (Hg) is the only metal liquid at room temp.
• Only nonmetal liquid at room temp: Bromine (Br) is the only nonmetal liquid at room temp.
• Solid halogen with smallest atomic mass: Iodine (I) is a solid halogen, and among halogens, Iodine has a smaller atomic mass than others (like Astatine) in solid state.
• Gas member of group 15: Nitrogen (N) is in group 15 and is a gas.
• Gas member of group 16: Oxygen (O) is in group 16 and is a gas.
• Gas member of group 1: Hydrogen (H) is in group 1 and is a gas.
• Alkali metal with smallest atomic mass: Lithium (Li) is an alkali metal (group 1) with the smallest atomic mass among alkali metals.
• Gas member of group 18 with least electron energy levels: Helium (He) is in group 18, has 1 electron energy level (least among group 18 gases).
• Solid member of nitrogen group (group 15) with smallest atomic mass: Phosphorus (P) is a solid in group 15, and has smaller atomic mass than other solid group 15 elements (like Arsenic).
• Solid member of oxygen group (group 16) with smallest atomic mass: Sulfur (S) is a solid in group 16, with smaller atomic mass than other solid group 16 elements (like Selenium).

Step2: Match each description to the element

1. Only metal that is liquid at room temperature: Mercury
2. Only nonmetal that is liquid at room temperature: Bromine
3. Solid halogen with the smallest atomic mass: Iodine
4. Gas member of group 15: Nitrogen
5. Gas member of group 16: Oxygen
6. Gas member of group 1: Hydrogen
7. Alkali metal with the smallest atomic mass: Lithium
8. Gas member of group 18 with the least number of electron energy levels: Helium
9. Solid member of the nitrogen group that has the smallest atomic mass: Phosphorus
10. Solid member of the oxygen group that has the smallest atomic mass: Sulfur

Answer:

1. Only metal that is liquid at room temperature: Mercury
2. Only nonmetal that is liquid at room temperature: Bromine
3. Solid halogen with the smallest atomic mass: Iodine
4. Gas member of group 15: Nitrogen
5. Gas member of group 16: Oxygen
6. Gas member of group 1: Hydrogen
7. Alkali metal with the smallest atomic mass: Lithium
8. Gas member of group 18 with the least number of electron energy levels: Helium
9. Solid member of the nitrogen group that has the smallest atomic mass: Phosphorus
10. Solid member of the oxygen group that has the smallest atomic mass: Sulfur