Question

Which of the following statements about the halogens is true?

• A. They all form $X^{-}$ ions
• B. They have the lowest ionization (potential) energies of the elements in their respective periods
• C. They are all solids
• D. They are among the best reducing agents
• E. They all react with water to form basic solutions

Answer 1

The correct option is A They all form $X^{-}$ ions

We know that all halogens have 7 electrons in their valence shell.

They need 1 electron to complete their octet and be stable.

Hence, if they accept this 1 electron from any other ion they get an extra negative charge on them.

Hence they all from negative ions as they need to accept an electron to complete their octet.