Help needed for chemistry equation

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg

Which can be observed only in a microscopic view? a) structure of a muscle cell b) shape of a soybean plant c) foam insulation d) x-ray of a knee joint

Using the periodic table, complete the following. element: hydrogen symbol: h₂ molecular weight: g mass of one mole: g/mol