only hve 20 mins please help

1 point Determine the number of neutrons in each of the following: a) has a mass number of 42 and atomic number of 20 b) has a mass number of 10 and 5 protons c) is a silicon atom with a mass number of 30 d) has a mass number of 9 and an atomic number of 4 e) has a mass number of 22 and 10 protons 1 point State the number of significant figures in each of the following measurements. a) 0.705m b) 680,000km c) 0.008090cm d) 28.050km e) 0.0005L