These are all chemical compounds:
N - NitrogenNO - Nitric oxideNO2 - Nitrogen dioxideHNO3 - Nitric acidCu(NO3)2 - Copper (II) nitrate
These are all chemical compounds:
N - Nitrogen
NO - Nitric oxide
NO2 - Nitrogen dioxide
HNO3 - Nitric acid
Cu(NO3)2 - Copper (II) nitrate