Calculate the [H+] if the [OH-] = 3.11 x 10^9 M(same sig figs!)

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.

How do scientists think that gravity affected the formation of our solar system?

Reactions in cells take place at about a. 40°c b. 0° c. 100°c d. 60°c