Science / Geology / Isotope: One of several forms of one element, all having the same number of protons in the nucleus, but differing in their number of neutrons and thus atomic weight.


Science / Biology / Radioisotope: Term applied to a radioactive isotope, such as carbon-14 or uranium 238. Radioisotope nuclei are unstable and spontaneously breakdown and emit one of a number of types of radiation. MORE

Isotope Geology

Science / Geology / Isotope Geology: The study of the relative abundances of isotopes in rocks to determine their ages (see geo-chronology) or conditions of formation. MORE


Science / Biology / Isotopes: Atoms with the same atomic number but different numbers of neutrons; indicated by adding the mass number to the elements name, e.g., carbon 12 or 12C. MORE

Iridium (Ir)

Science / Periodic Table of Elements / Iridium (Ir): Atomic number: 77, Atomic mass: 192.2 g.mol -1, Electronegativity: 2.2, Density: 22.4 at 20°C, Melting point: 2450 °C, Boiling point: 4527 °C, Vanderwaals radius: 0.126 nm, Ionic radius: 0.0 MORE

Krypton (Kr)

Science / Periodic Table of Elements / Krypton (Kr): Atomic number: 36, Atomic mass: 83.80 g.mol -1, Density: 3.73 10-3 at 20°C, Melting point: - 157 °C, Boiling point: - 153° C, Vanderwaals radius: 0.197 nm, Isotopes: 15, Electronic shell: [ MORE

Hydrogen (H)

Science / Periodic Table of Elements / Hydrogen (H): Atomic number: 1, Atomic mass: 1.007825 g.mol -1, Electronegativity: 2.1, Density: 0.0899*10 -3 -3 at 20 °C, Melting point: - 259.2 °C, Boiling point: - 252.8 °C, Vanderwaals radius: 0.12 nm, MORE