The general format AB+CD→AD+BC represents a reaction. A. exchange
B. replacement
C. decomposition
D. synthesis

What element breaks down into yttrium-90?

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.

Nonmetal halogen family atmoic mass 35