Top 10 elements facts

High density. Depleted uranium is 1.67 times as dense as lead, 84% as dense as osmium or iridium, which are the densest known substances under standard (i.e., Earth-surface) pressures. Consequently a depleted uranium projectile of given mass has a smaller diameter than an equivalent lead projectile, with less aerodynamic drag and deeper (armor-piercing) penetration due to a higher pressure at point of impact.

Helium was first discovered in 1868 as the unexpected line in the spectrum of the chromosphere of the Sun - and so it was named after the Greek word Helios (Sun).

Lead. When large deposit of graphite was found in the 16th century in England, it was thought to be a form of lead. In many languages, the word for pencil literally means lead pen. (German Bleistift, Polish ołówek, Arabic قلم رصاص)

In a high-mass star preceding Sun. Radioactive nickel-56 (which decays to the most common isotope of iron) is the last element to be produced before the collapse of a supernova. That is why the iron was abundantly scattered into space after the supernova explosion.

Iron is most abundant in the Earth's outer and inner core, and it is the fourth most common element in the Earth's crust.

Nutrients. A nutrient is a component in foods that is used by an organism to survive and grow. Macronutrients are broken down and converted into the energy needed by an organism's metabolic system to function. Micronutrients provide the necessary cofactors for metabolism to be carried out; they are also used to build and repair tissues and regulate body processes.

Silicon was identified as an element by the French physicist Antoine Lavoisier (1743-1794) in 1787. Stable silicon isotopes are 28Si, 29Si and 30Si. Silicon in nature occurs in the form of silicon dioxide and silicates, never in a free state. It plays an important role in the body - it is necessary along with vitamin C for proper collagen synthesis, conditions faster wound healing, improves the condition of hair, skin and nails, and removes aluminum from the body. It is also a good medium for actively growing tumors (eg leukemia and glioma), so it is forbidden to supplement it.

Three isotopes of hydrogen occur naturally on the Earth: the most frequent protium (1H), deuterium (2H) and tritium (3H). Other isotopes of hydrogen (4H-7H) were created in laboratories and are highly unstable.

Silver. A precious metal is a rare, naturally occurring metallic chemical element of high economic value. They are usually ductile and have a high lustre. Historically, precious metals were important as currency, but are now regarded mainly as investment and industrial commodities. Gold, silver, platinum, and palladium each have an ISO 4217 currency code.

Technetium. Many of technetium's properties were predicted by Dmitri Mendeleev, who left a gap in his periodic table before the element was discovered. It was finally discovered by Emilio Segrè and Carlo Perrier in 1937 and named after the Greek word τεχνητός, meaning "artificial", since it was the first element to be artificially produced.