1. Diagonal relationship
2. Carbon dioxide can be obtained as a solid in the form of dry ice, by allowing the liquied CO2 to expand rapidly. Dry ice is used as a refrigerant for ice-cream and frozen food.
3. Silicones are a group of organosilicon polymers containing R2SiO repeating units. Silicates are minerals with SiO4-4 as the basic structural unit. In silicates either the discrete unit is present or a number of such units are joined together via corners by sharing 1, 2, 3 or 4 oxygen atoms per silicate units.