Pls help me with this question. According to the following reaction, how many grams of chlorine gas are required for the complete reaction of 22.5 grams of phosphorus (P4)?

phosphorus (P4) (s) + chlorine (g) ---> phosphorus trichloride (l)

Many radioactive atoms that have large masses undergo radioactive decay by releasing a particle that is identical to a helium-4 nucleus. what changes in the original atom are expected as a result of this natural phenomenon? the atomic number and the mass number will decrease. the atomic number and the mass number will increase. the atomic number will increase, and the mass number will decrease. the atomic number will decrease, and the mass number will increase.