HELP PLEASE Excluding the noble gas group, how does the number of valence electrons in an element influence it chemical reactivity?

There are main groups in the modern periodic table of elements

What method(s) do plants use to obtain nitrogen? select all that apply. absorb it from the atmosphere use bacteria to convert nitrogen to usable form obtain usable nitrogen compounds from the soil absorb nitrogen from water taken in at the roots

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?