Q. Which of the following are correctly matched?

1. Mercury- liquid at room temperature
2. Iodine- non-lustrous
3. Lithium- low melting point
4. Graphite- good conductor

Select the correct answer from the codes given below:
Answer: Only 1, 3, and 4
Notes: All metals except mercury exist as solids at room temperature. Iodine is a non-metal but it is lustrous. Carbon is a non-metal that can exist in different forms. Each form is called an allotrope. Diamond, an allotrope of carbon, is the hardest natural substance known and has a very high melting and boiling point. Graphite, another allotrope of carbon, is a conductor of electricity. Alkali metals (lithium, sodium, potassium) are so soft that they can be cut with a knife. They have low densities and low melting points.

This question is part of UPSC Daily 20 MCQ Series Course on GKToday Android app.