Answer:
1) The elements have filled valence levels.
Explanation:
Since they have filled valence levels, they're stable and don't need to electrons to fill their valence shells since they're already full.
2) False, They do have electrons
3) False, He does have only one electron shell, but going down the periods, every next element have one more electron shell than a preceding one has.
4)False, they're actually the smallest atoms of their respective period
The properties of a compound are nothing like the properties of th elements that combine to make it.
sodium chloride,NaCl, table salt, is a white cubic crystal, stable ionic compound, soluble in water
sodium is a soft metal, very reactive with water and air
chlorine is a yellow green gas that is poisonous and very reactive.
carbon dioxide, CO2, is a clear, colorless gas that puts out fires, plants use but we breath out.
carbon is a black solid, or a diamond
oxygen is a clear colorless gas that is needed for burning and breathing.