How many elements are in the second group? (column)

Who is better, messi or cristiano, i need this for a chemistry class. asap

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Draw the structure for 5-isopropyl-2-methyl-3-nonene