3. Fertilisers supply the essential elements, nitrogen, phosphorus and potassium for plant growth. A bag of fertiliser contains 500 g of ammonium sulfate, (NH4)2SO4, and 500 g of potassium nitrate, KNO3.
Calculate the percentage by mass of nitrogen in the bag of fertiliser.

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Match the mixture with the substance// i really need on this guys (it’s a pic btw)

Fossil fuels are organic compounds that are made from