Elements are pure substances made up of molecules
Physical and chemical properties.
Sn=2
C and O=6
Im pretty confident yet I forgot a bit.
The nonmetals are divided into two categories: reactive nonmetals and noble gases. Noble gases are in group 18: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). hope this helps