Which of the following statements is correct regarding the size of ions compared to their parent atoms?

• A
  $X^{-}$ ion is larger in size than $X$ atom
• B
  $X^{+}$ ion is larger in size than $X$ atom
• C
  $X^{+}$ ion is larger in size than $X^{-}$ ion
• D
  $X^{+}$ and $X^{-}$ ions are equal in size