A water solution whose ph is 4 is always acids right?

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.

Surface currents are caused by blank space . question 14 options: surface currents are caused by? differences in water temperature high salinity differences in density wind forces

How can the periodic table be used to predict the behavior of elements?