this is the answer of your question .
<em>Hope</em><em> </em><em>it</em><em> </em><em>helped </em><em>you</em>
Answer: 8
Explanation: Radon has 8 valence electrons. Radon is considered stable with a complete octet of electrons, filling the s and p orbitals.
Mercury is the only metal that is a liquid at room temperature.
your answer is A.
It is used in thermometer.