In simple terms Isotopes are versions of the same element. They carry the same number of protons, which is what makes them that element, but different numbers of neutrons. The International Atomic Energy Agency puts it simply: isotopes share almost the same chemical properties but differ in mass. How it works An isotope is named
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons, so they differ in mass.
Krypton is the chemical element with atomic number 36 and the symbol Kr. It is a colorless, odorless noble gas in group 18 of the periodic table, and it is one of the rarest gases in Earth’s atmosphere. Krypton is used in energy-saving lighting, flash lamps and some lasers, and it once helped define the
A colorless, odorless noble gas with atomic number 36 that is one of the rarest gases in air and is used in lighting and lasers.
Lead is the chemical element with atomic number 82 and the symbol Pb. It is a dull, silvery-gray metal that is soft and easily worked into sheets. Lead has been mined for thousands of years, and although it is still widely used in batteries and radiation shielding, many older uses have been banned or discouraged
A soft, dull silvery-gray metal with atomic number 82, used in batteries and radiation shielding and toxic to people.
Lithium is the chemical element with atomic number 3 and the symbol Li. It is a soft, silvery alkali metal in group 1 of the periodic table, and it has the lowest density of any metal. Lithium is best known today as the key ingredient in rechargeable batteries, although it also has long-standing uses in
The lightest metal, atomic number 3, a soft silvery alkali metal widely used in rechargeable batteries.
Magnesium is the chemical element with atomic number 12 and the symbol Mg. It is a silvery-white alkaline earth metal in group 2 of the periodic table, light enough to be used in aircraft and electronics, and it burns with a brilliant white light. Magnesium sits at the center of chlorophyll, the green pigment that
A light, silvery-white alkaline earth metal with atomic number 12 that burns brightly and sits at the center of chlorophyll.
Manganese is the chemical element with atomic number 25 and the symbol Mn. It is a hard, brittle, silvery metal in group 7 of the periodic table, and almost all of it is used to make steel and other alloys. The element is also essential to living things, including humans. History of manganese People used
A hard, brittle, silvery metal with atomic number 25, used mainly in steel and essential to living things.
Mercury is the chemical element with atomic number 80 and the symbol Hg. It is a silvery metal that is liquid at room temperature. Because of its toxicity, many former uses of mercury, including thermometers and some lamps and batteries, have been phased out or are under review. History of mercury Cinnabar, also called vermilion
A silvery metal with atomic number 80 that is liquid at room temperature and toxic, so many uses are being phased out.
In simple terms A mole is a counting unit for very small things. One mole is a fixed number of particles, the way a dozen is a fixed number of eggs. The number is enormous because atoms are tiny. NIST calls the mole a shorthand way to talk about huge numbers, especially of tiny things.
A mole is the SI unit of amount of substance: exactly 6.02214076 times 10 to the power 23 entities, such as atoms, molecules or ions.
In simple terms A molecule is a group of atoms bonded together and behaving as one unit. Water is the familiar case: hydrogen and oxygen atoms joined into a single particle. The atoms on their own are gases with nothing watery about them. How it works IUPAC, the body that sets chemical terminology, defines a
A molecule is an electrically neutral group of two or more atoms held together as a single unit by chemical bonds.
Neon is the chemical element with atomic number 10 and the symbol Ne. It is a colorless, odorless noble gas in group 18 that glows reddish orange when electricity passes through it at low pressure, which is the basis of the neon sign. Neon is chemically almost inert, and it is rare in Earth’s atmosphere
An inert, colorless noble gas with atomic number 10 that glows red-orange in discharge tubes and is used in neon signs.