Cases of word usage

1) the smallest unit of a chemical element (atom)

2) a non-metallic element (symbol C) that occurs in all living matter, in its pure form as diamonds and graphite and in an impure form as coal and charcoal (carbon)

3) an element (symbol Cr) used for covering taps etc and in stainless steel (chromium)

4) any kind of chemical substance made of oxygen and another chemical element (oxide)

5) a yellow, non-metallic element (symbol P) which catches fire easily and gives out a faint light in the dark (phosphorus)

6) the absence of some necessary quality or element (poorness)

7) a non-metallic element (symbol Si) found in sand, granite etc, used in electronics and alloys (silicone)