If you have 2.4x10^24 atoms of copper, how many moles of copper do you have

a 0.250
b 4.00
c 0.600
d 3.00
e none of above

How many neutrons does a atom of cobalt have?

Which other elements contain the same number of outer electrons as sodium

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules