Science / Chemistry / Isotope: Atoms or ions of an element with different numbers of neutronsin their atomic nucleus. Isotopes have the same atomic number but different mass number. Isotopes have very similar chemical properties but sometimes differ greatly in nuclear stability.


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