1. Sodium is very reactive and may burn on exposure to air. Therefore, it is kept under _______.   water   acids   oil   ice   Hint Half-n-half Clue   2. Metals are usually good conductors of heat and electricity.   True   False   3. To prevent corrosion, metals are often galvanized by covering them with a layer of _______.   sodium   zinc   copper   tin   Half-n-half Clue   4. Which metal is extracted from the ore 'hematite'?   Iron   Aluminum   Manganese   Tin   Half-n-half Clue   5. Which of the following metals is a liquid at room temperature?   Tungsten   Mercury   Cadmium   Sodium   Half-n-half Clue   6. Iron is magnetic in nature.   True   False   7. Which of the following metals is often found in the pure state?   Iron   Gold   Magnesium   Aluminum   Half-n-half Clue