1. Chemical Formulas
Scientists developed a shorthand method of representing elements and compounds.
Chemical Symbol: Either a single capital letter of capital letter followed by a lower case letter represents each element.
Ca – calcium Ne – neon Co - cobalt
C – carbon N – nitrogen CO – carbon, oxygen
Chemical Formula: A combination of symbols representing a particular compound. It indicates the elements in the compound and the proportion in which they are present.
NaCl – 1 sodium atom, 1 chlorine atom
Cu2O4 – 2 copper atoms, 4 oxygen atoms

2. Activity!!
Explain the meaning of each letter and number in the following chemical formulas.
a) NaHCO3 (sodium bicarbonate – baking soda)
b) CaCO3 (calcium carbonate – chalk)
c) CuSO4 (copper II sulphate)
d) C9H8O4 (acetylsalicylic acid – aspirin)