Answer:
3. True
4.
a. solid non-metals are brittle
b. They have usually lower densities than metals
Explanation:
Non metals are mostly gases. Out of the 17 non-metals, 11 are gases in room temperature. Bromine is the only non-metal that is liquid at room temperature, and the last 5 are solids.
They have lower densities than metals but their densities vary. Solid non-metals are charaterized as brittle.
The last two options are properties of metals, and non-metals show opposite properties, meaning they lack luster (are not shiny) and are poor cnductors of heat and electricity, which is why they are often used as insulators.
