Why will frequency decrease when wave gets longer

Can someone me with these questions plz.

For each of the following types of reactions, write a general reaction formula in the symbolic form—for example, a + b → ab. single-displacement double-displacement synthesis decomposition

Which of the following did jj thompson discover about atoms? a)an atom has an internal structure. b) atoms are tiny indivisible particles. c)electrons orbit the nucleus of an atom. d) the nucleus of an atom contains protons and neutrons.