Q and R are elements in the same period of the Periodic Table. Q contains 7 electrons in its outer shell, and R contains 2 electrons in its outer shell. Which statement about Q and R is correct?
- AQ is a metal and R is a non-metal.
- BQ and R have different numbers of electron shells.
- CR is found to the right of Q in the Periodic Table.
- DThe proton number of R is less than the proton number of Q.