Which is not classified as a particulate? a. ozone b. lead c. ash d. dust

Ozone is not classified as particulate.

A particulate is a very small solid particle that can exist in suspension in both liquid and a gas. This  particle remains suspended because it does not dissolve in the liquid or gas that it is suspended in. Dust and ash are capable of being particulates in both gases and liquids. Lead has been known to be a particulate in water, acting as a contaminant.

On the other hand, ozone is a gas that exists as a molecule of three oxygen atoms bonded together. For this reason, Ozone can not be particulate. The correct answer is A.Ozone.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

it's filtration, but this is an assumption so my apologies if i got this