Hydrocarbons are compounds that contain(1) carbon, only(2) carbon and hydrogen, only(3) carbon, hydrogen, and oxygen, only(4) carbon, hydrogen, oxygen, and nitrogen, only24

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.

Which best describes why nh4+ can form an ionic bond with ci-?

In 2002, the rare earth elements mine in mountain pass, california was closed because