What particle has a mass & charge? a. alpha particle
b. beta particle
c. gamma ray

Which of the following did jj thompson discover about atoms? a)an atom has an internal structure. b) atoms are tiny indivisible particles. c)electrons orbit the nucleus of an atom. d) the nucleus of an atom contains protons and neutrons.

Which symbol can be used to indicate the pressure at which a chemical reaction is carried out? 25°c 2 atm pa

Which radioisotope is used to date fossils? a. oxygen-16 b. carbon-14 c. uranium-238 d. carbon-12