I need help!! i’ll give 20 points

Positrons are spontaneously emitted from the nuclei of

Coal contains energy. a. light b. kinetic c. chemical d. mechanical

What do the atoms of elements in the same group have in common? a. they have the same atomic numbers. b. they have the same average atomic masses. c. they have the same number of electron shells. d. they have the same number of electrons in their outermost shells.