Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is almost colorless, but it readily combines with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (Ra3N2).
Read key information and facts about element Radium
|Classification||alkaline earth metal|
|Group in Periodic Table||2|
|Group Name||beryllium family|
|Period in Periodic Table||7|
|Block in Periodic Table||s-block|
|Electronic Configuration||[Rn] 7s2|
|Melting Point||700 °C|
|Boiling Point||1737 °C|
|Electronic Shell Structure||[2, 8, 18, 32, 18, 8, 2]|
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 88 to find Radium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Radium on periodic table look for cross section of group 2 and period 7 in the modern periodic table.
The element Radium was discovered by Pierre Curie in year 1898 in France . Radium derived its name from the Latin radius, 'ray'
The table below shows the abundance of Radium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
|Ppb by weight (1ppb =10^-7 %)|
|Abundance in Universe||N/A|
|Abundance in Sun||N/A|
|Abundance in Meteorites||N/A|
|Abundance in Earth's Crust||9.9×10-12%|
|Abundance in Oceans||1×10-15%|
|Abundance in Humans||1×10-13%|
The solid state structure of Radium is Body Centered Cubic.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
and the angles between them Lattice Angles (alpha, beta and gamma).
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
|Space Group Name||Im_ 3m|
|Space Group Number||229|
|Crystal Structure||Body Centered Cubic|
Radium atoms have 88 electrons and the electronic shell structure is [2, 8, 18, 32, 18, 8, 2] with Atomic Term Symbol (Quantum Numbers) 1S0.
|Number of Electrons (with no charge)||88|
|Number of Protons||88|
|Number of Neutrons||138|
|Shell structure (Electrons per energy level)||[2, 8, 18, 32, 18, 8, 2]|
|Electron Configuration||[Rn] 7s2|
|Atomic Term Symbol (Quantum Numbers)||1S0|
Shell Structure of Radium - Electrons per energy level
The ground state electronic configuration of Neutral Radium atom is [Rn] 7s2. The portion of Radium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Rn]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used.This is important as it is the Valence electrons 7s2, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Radium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 7s2
Radium atomic radius is N/A, while it's covalent radius is N/A.
|Atomic Volume||45.2 cm3|
|Van der Waals Radius||N/A|
|Neutron Cross Section||20 σa/barns|
The electron affinity of Radium is N/A
Refer to table below for Ionization energies of Radium
|Ionization energy number||Enthalpy - kJ/mol|
Refer to below table for Radium Physical Properties
|Molar Volume||45.2 cm3|
Radium is Conductor of electricity. Refer to table below for the Electrical properties of Radium
|Electrical Conductivity||1×106 S/m|
|Resistivity||1×10-6 m Ω|
|Thermal Conductivity||19 W/(m K)|
|Mass Magnetic Susceptibility||N/A|
|Molar Magnetic Susceptibility||N/A|
|Volume Magnetic Susceptibility||N/A|
|Speed of Sound||N/A|
Refer to table below for Thermal properties of Radium
|Melting Point||973 K (700 °C)|
|Boiling Point||2010 K (1737 °C)|
|Heat of Fusion||8 kJ/mol|
|Heat of Vaporization||125 kJ/mol|
|Heat of Combustion||N/A|
Isotopes of rhodium. Naturally occurring Radium has 1 stable isotope - None.
|Isotope||Isotope Mass||% Abundance||T half||Decay Mode|
|DOT Hazard Class||N/A|
|NFPA Fire Rating||N/A|
|NFPA Health Rating||N/A|
|NFPA Reactivity Rating||N/A|
List of unique identifiers to search the element in various chemical registry databases
|CAS Number - Chemical Abstracts Service (CAS)||CAS7440-14-4|
|Alkali Metals||Alkaline Earth Metals|
|Transition Metals||Post-Transition Metals|