Periodic table

4. - Fluorine is the most receptive and electronegative of all the chemical elements. It doesn’t respond with oxygen, helium, neon, and argon.
6. - Beryllium is two-thirds the density of aluminum and has six times the specific stiffness of steel by weight. Beryllium ceramics are used to focus and control eye surgery lasers.
7. - The amount of carbon on Earth is relatively constant; it’s simply transformed from one form to another by the carbon cycle. Impure carbon (e.g. charcoal from wood and coke from coal) is used in metal smelting. The iron and steel industries depend on it.
9. -Although it’s rare on Earth, Hydrogen is the most common element in the universe. Hydrogen can be combined with carbon dioxide to make methanol or dimethyl ether (DME) which are important transport fuels.

1. - Lithium is the lightest of all the metals and can easily float on water. Lithium chloride is one of the most hygroscopic (absorbs moisture from the air) materials known and is used in air conditioning and industrial drying systems (as is lithium bromide).
2. - Although abundant on Earth, sodium is never naturally found in its pure form; it forms compounds with other elements.
3. - Helium atoms are so light that they can escape Earth's gravity! Helium is used in rocket propulsion (to pressurize fuel tanks, especially those for liquid hydrogen, because only helium is still a gas at liquid-hydrogen temperature).
5. - Neon is mainly found in stars. Neon is the 5th most common element in the universe but comprises only 0.0018% of the Earth's atmosphere.
8. - Oxygen is the third most abundant element in the universe; however, its reactivity made it relatively rare in Earth's early atmosphere.