- 🇬🇧 Radium
- 🇺🇦 Радій
- 🇨🇳 鐳
- 🇳🇱 Radium
- 🇫🇷 Radium
- 🇩🇪 Radium
- 🇮🇱 רדיום
- 🇮🇹 Radio
- 🇯🇵 ラジウム
- 🇵🇹 Rádio
- 🇪🇸 Radio
- 🇸🇪 Radium
- 🇷🇺 Радий
- Name: radium
- Symbol: Ra
- Atomic number: 88
- Relative atomic mass (Ar): [ 226 ] (longest lived isotope)
- Standard state: solid at 298 K
- Appearance: metallic
- Classification: Metallic
- Group in periodic table: 2
- Group name: Alkaline earth metal
- Period in periodic table: 7
- Block in periodic table: s
- Shell structure: 2.8.18.32.18.8.2
- CAS Registry: 7440-14-4
Radium atoms have 88 electrons and the shell structure is 2.8.18.32.18.8.2. The ground state electronic configuration of neutral radium is [Rn].7s2 and the term symbol of radium is 1S0.
Radium: description
Pure metallic radium is brilliant white when freshly prepared, but blackens on exposure to air, probably due to formation of the nitride. It exhibits luminescence, as do its salts; it decomposes in water and is somewhat more volatile than barium. Radium imparts a carmine red colour to a flame.
Radium emits α, β, and γ rays and when mixed with beryllium produces neutrons. Inhalation, injection, or body exposure to radium can cause cancer and other body disorders. alkaline earth metal, white but tarnishes black upon exposure to air, luminesces, decomposes in water, emits radioactive radon gas, disintegrated radioactively until it reaches stable lead, radiological hazard, α, β, and γ emitter, exposure to radium can cause cancer and other body disorders. Radium is over a million times more radioactive than the same mass of uranium.
radium
Radium paint was used in the mid 1900s to paint the hands and numbers of some clocks and watches. The paint was composed of radium salts and a phosphor and glowed in the dark. Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.
Radium: physical properties
- Density of the chemical elements on a miniature periodic table spark table Density of solid: 5000 kg m-3
- Molar volume of the chemical elements on a miniature periodic table spark table Molar volume: 41.09 cm3
- Thermal conductivity of the chemical elements on a miniature periodic table spark table Thermal conductivity: 19 W m‑1 K‑1
Radium: heat properties
- Melting point on a miniature periodic table spark table Melting point: 973 [700 °C (1292 °F)] K
- Boiling point on a miniature periodic table spark table Boiling point: 2010 [1737 °C (3159 °F)] K
- Enthalpy of fusion on a miniature periodic table spark table Enthalpy of fusion: 20.5 kJ mol-1
Radium: atom sizes
- Atomic radius (empirical) of the chemical elements on a miniature periodic table spark table Atomic radius (empirical): 215 pm
- Covalent (single bond) radius on a periodic table spark table Molecular single bond covalent radius: 201 (coordination number 2) ppm
- van der Waals radius on a periodic table spark table van der Waals radius: 281 ppm
Radium: electronegativities
- Pauling electronegativity of the chemical elements on a miniature periodic table spark table Pauling electronegativity: 0.9 (Pauling units)
- Allred-Rochow electronegativity of the chemical elements on a miniature periodic table spark tableAllred Rochow electronegativity: 0.97 (Pauling units)
- Mulliken-Jaffe electronegativity of the chemical elements on a miniature periodic table spark tableMulliken-Jaffe electronegativity: 0.92 (sp orbital)
Radium: orbital properties
- First ionization energy the chemical elements on a miniature periodic table spark table First ionisation energy: 509.29 kJ mol‑1
- Second ionization energy the chemical elements on a miniature periodic table spark table Second ionisation energy: 979.05 kJ mol‑1
- Third ionization energy the chemical elements on a miniature periodic table spark table Third ionisation energy: 2990 kJ mol‑1
Radium: abundances
- Chemical elements abundance by weight in the universe on a miniature periodic table spark tableUniverse: (no data) ppb by weight
- Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark tableCrustal rocks: 0.00010 ppb by weight
- Chemical elements abundance by weight in humans on a miniature periodic table spark tableHuman: 0.000001 ppb by weight
Radium: crystal structure
Radium: biological data
- Human abundance by weight of the chemical elements on a miniature periodic table spark table Human abundance by weight: 0.000001 ppb by weight
Radium has no biological role.
Radium: uses
Radium: reactions
Reactions of radium as the element with air, water, halogens, acids, and bases where known.
Radium: binary compounds
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of radium where known.
Radium: compound properties
Bond strengths; lattice energies of radium halides, hydrides, oxides (where known); and reduction potentials where known.
Radium: history
Radium was discovered by Pierre and Marie Curie in 1898 at France. Origin of name: from the Latin word "radius" meaning "ray".Radium: isotopes
Radium: isolation
Isolation: all isotopes of radium are radioactive and there is only ever any need to make radium metal on very small scales for research purposes. Radium is extremely scarce but found in uranium ores such as pitchblende at slightly more than 1g in 10 tonnes of ore. It may be made on very small scale by the electrolysis of molten radium chloride, RaCl2. This was first done using a mercury cathode, which gave radium amalgam. The metal was obtained by distillation away from the amalgam.
cathode: Ra2+(l) + 2e- → Ra
anode: Cl-(l) → 1/2Cl2 (g) + e-