Q. Consider the following statements:

1. Radon is the heaviest gas.
2. Astatine is the rarest element on the earth.
3. Graphite, which is a non-metal, is also an electrical conductor.

Which of the above statement(s) is/are correct?
Answer: 1, 2 and 3
Notes: Radon is the heaviest known noble gas and is radioactive. Astatine, with the atomic number 85, is the rarest naturally occurring element in the Earth's crust. Graphite, a form of carbon, is the only non-metal that conducts electricity due to its delocalised electrons. Thus, all the statements are correct.