Radium Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
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).
It belongs to group 2 of the periodic table having trivial name alkaline earth metals*. You can also download Printable Periodic Table of Elements Flashcards for Radium in a PDF format.
Radium Facts
Read key information and facts about element Radium
Name | Radium |
Atomic Number | 88 |
Atomic Symbol | Ra |
Atomic Weight | 226 |
Phase | Solid |
Color | Silver |
Appearance | silvery white metallic |
Classification | Alkaline Earth Metal |
Natural Occurance | From decay |
Group in Periodic Table | 2 |
Group Name | beryllium family |
Period in Periodic Table | period 7 |
Block in Periodic Table | s-block |
Electronic Configuration | [Rn] 7s2 |
Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 32, 18, 8, 2 |
Melting Point | 973 K |
Boiling Point | 2010 K |
CAS Number | CAS7440-14-4 |
How to Locate Radium on Periodic Table
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.
Radium History
The element Radium was discovered by P. and M. Curie in year 1898 in France. Radium was first isolated by M. Curie in 1902. Radium derived its name from the Latin radius, 'ray'.
Discovered By | P. and M. Curie |
Discovery Date | 1898 in France |
First Isolation | 1902 |
Isolated by | M. Curie |
The Curies reported on December 26, 1898, a new element different from polonium, which Marie later isolated fromuraninite.
Radium Uses
Radium is used as a neutron source and is also used to produce radon. One gram of radium-226 will make .0001 mL of radon each day. The element is 1,000,000 times more active than uranium.
Radium Presence: Abundance in Nature and Around Us
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 %) | ppb by atoms (1ppb =10^-7 %) | |
---|---|---|
Abundance in Universe | - | - |
Abundance in Sun | - | - |
Abundance in Meteorites | - | - |
Abundance in Earth's Crust | 0.00010 | 0.00001 |
Abundance in Oceans | 0.00000001 | 0.0000000003 |
Abundance in Humans | 0.000001 | 0.00000003 |
Crystal Structure of Radium
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.
Unit Cell Parameters
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)
a | b | c |
---|---|---|
514.8 pm | 514.8 pm | 514.8 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
π/2 | π/2 | π/2 |
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 |
Number of atoms per unit cell | 2 |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Radium Atomic and Orbital Properties
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.
Atomic Number | 88 |
Number of Electrons (with no charge) | 88 |
Number of Protons | 88 |
Mass Number | 226 |
Number of Neutrons | 138 |
Shell structure (Electrons per energy level) | 2, 8, 18, 32, 18, 8, 2 |
Electron Configuration | [Rn] 7s2 |
Valence Electrons | 7s2 |
Valence (Valency) | 2 |
Main Oxidation States | 2 |
Oxidation States | 2 |
Atomic Term Symbol (Quantum Numbers) | 1S0 |
Bohr Atomic Model of Radium - Electrons per energy level
n | s | p | d | f |
---|
Ground State Electronic Configuration of Radium - neutral Radium atom
Abbreviated electronic configuration of Radium
The ground state abbreviated 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.
Unabbreviated electronic configuration of neutral Radium
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
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.
As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
Atomic Structure of Radium
Radium atomic radius is -, while it's covalent radius is -.
Atomic Radius Calculated | - |
Atomic Radius Empirical | 215 pm (2.15 Å) |
Atomic Volume | 41.09 cm3/mol |
Covalent Radius | - |
Van der Waals Radius | 283 pm |
Neutron Cross Section | 20 |
Neutron Mass Absorption | - |
Spectral Lines of Radium - Atomic Spectrum of Radium
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.
Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.
Emission spectrum of Radium
Absorption spectrum of Radium
Radium Chemical Properties: Radium Ionization Energies and electron affinity
The electron affinity of Radium is -.
Valence | 2 |
Electronegativity | 0.9 |
ElectronAffinity | - |
Ionization Energy of Radium
Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).
Refer to table below for Ionization energies of Radium
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1st | 509.3 |
2nd | 979 |
Radium Physical Properties
Refer to below table for Radium Physical Properties
Density | 5 g/cm3 |
Molar Volume | 41.09 cm3/mol |
Elastic Properties
Young Modulus | - |
Shear Modulus | - |
Bulk Modulus | - |
Poisson Ratio | - |
Hardness of Radium - Tests to Measure of Hardness of Element
Mohs Hardness | - |
Vickers Hardness | - |
Brinell Hardness | - |
Radium Electrical Properties
Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).
Radium is a conductor of electricity. Refer to table below for the Electrical properties of Radium
Electrical conductors | Conductor |
Electrical Conductivity | 1000000 S/m |
Resistivity | 0.000001 m Ω |
Superconducting Point | - |
Radium Heat and Conduction Properties
Thermal Conductivity | 19 W/(m K) |
Thermal Expansion | - |
Radium Magnetic Properties
Magnetic Type | - |
Curie Point | - |
Mass Magnetic Susceptibility | - |
Molar Magnetic Susceptibility | - |
Volume Magnetic Susceptibility | - |
Optical Properties of Radium
Refractive Index | - |
Acoustic Properties of Radium
Speed of Sound | - |
Radium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Radium
Melting Point | 973 K(699.85 °C, 1291.730 °F) |
Boiling Point | 2010 K(1736.85 °C, 3158.330 °F) |
Critical Temperature | - |
Superconducting Point | - |
Enthalpies of Radium
Heat of Fusion | 8 kJ/mol |
Heat of Vaporization | 125 kJ/mol |
Heat of Combustion | - |
Radium Isotopes - Nuclear Properties of Radium
Radium has 33 isotopes, with between 202 and 234 nucleons. Radium has 0 stable naturally occuring isotopes.
Isotopes of Radium - Naturally occurring stable Isotopes: -.
Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|---|---|
202Ra | 88 | 114 | 202 | Synthetic | ||
203Ra | 88 | 115 | 203 | Synthetic | ||
204Ra | 88 | 116 | 204 | Synthetic | ||
205Ra | 88 | 117 | 205 | Synthetic | ||
206Ra | 88 | 118 | 206 | Synthetic | ||
207Ra | 88 | 119 | 207 | Synthetic | ||
208Ra | 88 | 120 | 208 | Synthetic | ||
209Ra | 88 | 121 | 209 | Synthetic | ||
210Ra | 88 | 122 | 210 | Synthetic | ||
211Ra | 88 | 123 | 211 | Synthetic | ||
212Ra | 88 | 124 | 212 | Synthetic | ||
213Ra | 88 | 125 | 213 | Synthetic | ||
214Ra | 88 | 126 | 214 | Synthetic | ||
215Ra | 88 | 127 | 215 | Synthetic | ||
216Ra | 88 | 128 | 216 | Synthetic | ||
217Ra | 88 | 129 | 217 | Synthetic | ||
218Ra | 88 | 130 | 218 | Synthetic | ||
219Ra | 88 | 131 | 219 | Synthetic | ||
220Ra | 88 | 132 | 220 | Synthetic | ||
221Ra | 88 | 133 | 221 | Synthetic | ||
222Ra | 88 | 134 | 222 | Synthetic | ||
223Ra | 88 | 135 | 223 | Synthetic | ||
224Ra | 88 | 136 | 224 | Synthetic | ||
225Ra | 88 | 137 | 225 | Synthetic | ||
226Ra | 88 | 138 | 226 | Synthetic | 1.59×10^3 years | AlphaEmission |
227Ra | 88 | 139 | 227 | Synthetic | ||
228Ra | 88 | 140 | 228 | Synthetic | ||
229Ra | 88 | 141 | 229 | Synthetic | ||
230Ra | 88 | 142 | 230 | Synthetic | ||
231Ra | 88 | 143 | 231 | Synthetic | ||
232Ra | 88 | 144 | 232 | Synthetic | ||
233Ra | 88 | 145 | 233 | Synthetic | ||
234Ra | 88 | 146 | 234 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.
NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.
The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.
NFPA Fire Rating | N/A | N/A |
NFPA Health Rating | N/A | N/A |
NFPA Reactivity Rating | N/A | N/A |
NFPA Hazards | N/A |
Autoignition Point | - |
Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
Database | Identifier number |
---|---|
CAS Number - Chemical Abstracts Service (CAS) | CAS7440-14-4 |
RTECS Number | - |
CID Number | CID6328144 |
Gmelin Number | Gmelin40437 |
NSC Number | - |
Compare Radium with other elements
Compare Radium with Group 2, Period 7 and Alkaline Earth Metal elements of the periodic table.
Compare Radium with all Group 2 elements
Compare Radium with all Period 7 elements
Compare Radium with all Alkaline Earth Metal elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Radium