Simply any atom can be presented in the form of a tiny, but massive kernel around which on circular or elliptic orbits electrons rotate. Chemical properties of an element depend on the external "valent" electrons which are taking part in formation of a chemical bond with other atoms. Atom can "give" the electrons, and can "accept" strangers. In the second case it means that atom shows nonmetallic properties, that is, is nonmetal. Why does it depend?

Fluorine (the Latin name – Fluorum) – an element of the main subgroup of the VII group of the table of D.I. Mendeleyev, halogen. It has atomic number 9 and atomic mass about 19. Under normal conditions it is pale yellow diatomic gas with a pungent suffocating smell.

Oxygen is in Mendeleyev's table in the second period, the main subgroup of the VI group. This chemical element has serial number 8 and atomic mass about 16. Along with sulfur, selenium, tellurium and polonium, it belongs to chalcogens.

Carbon is the chemical element which is in the 4th group of a periodic system. There are two most studied allotropic modifications of carbon - graphite and diamond. The last is widely used in the industry and jewelry.