* Is the lightest metal - lithium
* The heaviest metal is - osmium
* Is the hardest metal - Platinum
* The hardest thing is - diamond
* The most perfect coal is - Anthracite
* The pure form of water - rain water
* Marsh is called gas - Methane
* Nobel Gas - Helium
* Widowed stream is measured - from ammeter
* The main ore of mercury is - Cinebar