An atom contains 16 protons, 18 neutrons and 16 electrons? What is its mass number?
Name the element of which this is an isotope?
What are the isotopes of the element Hydrogen? (chemical term, ex Carbon-14)
Define the term isotope
Name these two isotopes (common terms)
Describe how these isotopes differ.

Two people each hold the end of a rope and create waves by moving their arms up and down. this wave is best classified as a transverse wave because a) both the rope particles and the wave are moving in the same direction. b) the wave is moving up and down as the particles of the rope move horizontally. c) the wave is moving horizontally as the particles of the rope move up and down. eliminate d) the wave is moving in a parallel direction with the motion of the person's arms.