Radium Chemical Properties (25 Facts You Should Know)

Ra or Radium is the only radioactive alkaline earth metal and is formed upon decay. Let us discuss the chemical properties of Radium in detail.

Ra is present in the same group as Ba and next to it, so it has chemical and physical properties most closely resemble its lighter congener. In its pure form, it appears silvery white but it readily reacts with nitrogen in open exposure to air due to its reactive nature and formed a black surface on the metal.

Ra can react more rapidly with nitrogen rather than oxygen to form Ra₃N₂. In its pure form, it is volatile in nature. Now we will discuss the basic chemical properties of Radium with a proper explanation in this article.

1.  Radium symbol

Symbol is used to express an element by using one or two letters of the English or Latin alphabet of the chemical name. Let us predict the atomic symbol of Radium.

“Ra” is the atomic symbol of Radium as the name of the element starts with the R letter in the English alphabet but the letter R is already taken for the organic chemistry alkyl group, so we use the first two letters of the spelling Radium like “Ra” instead of the first letter to distinguish the element.

2. Radium group in the periodic table

Vertical lines or columns of the periodic table are referred as the group of the periodic table. Let us predict the group of Radium in the periodic table.

Ra is placed in the 2^nd vertical series of the periodic table by its atomic number by Mendeleev. So, it is 2^nd group element, or in the modern periodic table it is placed in group IIA, and it is distinguished on the precipitation table.

3. Radium period in the periodic table

A horizontal line or row of the periodic table where every element is placed by its last principle quantum number is called a period. Now predict the period of Radium.

Ra is placed in the 7^th period as it contains more than 86 electrons, which are placed in the above 6 periods. So the remaining two electrons is placed in the 7^th period, which is in the radioactive period of the periodic table as 6^th period consists of lanthanide series of 14 elements.

4. Radium block in the periodic table

The orbital where the valence electrons of the element are present is called the block of the periodic table. Let us predict the block of Radium.

Radium belongs to the s block element as the valence electrons are present in its 7s orbital, and it is an alkaline earth metal like Calcium. It contains p, d and f orbitals also but the outermost orbital for Ra is s of 7 principle quantum number, so it is an s-block element.

5. Radium atomic number

The value of Z, known as the atomic number is the total number of electrons. Let us find the atomic number of Radium.

The total atomic number of Radium is 86 which means it has 86 electrons and protons because we know the number of protons is always equal to the number of electrons and for this reason, they become neutral due to the neutralization of equal and opposite charges.

6. Radium Atomic Weight

The mass of the element is called weight which is measured with respect to some standard value. Let us calculate the atomic weight of Radium.

The atomic weight of Radium is 226 on the 12C scale, which means the atomic weight of carbon is 137/12^th part. But the actual value is 226.0254, which is the average value of different isotopes of Radium.

7. Radium Electronegativity according to Pauling

Pauling electronegativity is the power to attract any other element for that particular atom. Let us predict the electronegativity of Radium.

The Pauling electronegativity is 0.89 for Ra, which means it is more electropositive and less electronegative as its value is less than 1. So, it has less ability to attract any other element liker other alkaline earth metals.

8. Radium atomic Density

The number of atoms presents per unit volume of any atom is called the atomic density of that respective element. Let us calculate the atomic density of Radium.

The atomic density of Radium is 5 g/cm³ which means the weight of atoms per unit volume of Ra is calculated to be 5. The atomic weight is divided by the standard volume value of the element by Avagardo’s value of 22.4 L at STP.

• Density is calculated by the formula, atomic density = atomic mass / atomic volume
• The atomic mass or weight of the Radium atom is 226.0254 g which is established
• The volume of the Radium molecule is 22.4 liter at STP as per Avogardo’s calculation 
• So, the atomic density of the Radium atom is, 226.0254/(22.4*2) = 5.04  g/cm³

9. Radium melting point

Changing to a liquid state from its solid state at a particular temperature is called the melting point of that particular element. Let us find the melting point of Radium atom.

The melting point of Radium atom is 700⁰ C or 973K temperature because Ra has a body-centered cubic lattice in the crystal form when it exists in a solid state and needs greater energy to break that crystal, so it has a lower melting point than Ba.

10. Radium boiling point

Where the vapor pressure of an element becomes equal to its atmospheric pressure is called the boiling point. Let us find the boiling point of Radium.

The boiling point of Radium atom is 1737⁰ C or 2010K because it has a higher melting point, so it needs more energy than the melting point for boiling. If the element does not exist in liquid form then it cannot be boiled off.

11. Radium Van der Waals radius?

Van der Waal’s radius is the distance between the center of two atomic spheres attached together. Let us find the van der Waal’s radius of Radium.

The Van der Waal’s radius for Ra is 283 pm as it contains a 7s orbital and the 7s orbital has greater spatial distribution. So, it has a greater radius than Ba as it contains a 7s orbital.

• Van der Waal’s radius is, R_v = d_A-A / 2
• Where R_V stands for Van Waal’s radius of the molecule of spherical shape
• d_A-A is the distance between two adjacent spheres of the atomic molecule or summation of sue radius of two atomic

12. Radium ionic radius

The summation of cation and anion is called the ionic radius of the element. Let us find the ionic radius of radium.

The ionic radius of Ra is 283pm is the same as van der Waal’s radius, because in the ionic form it has the same ionic value.

13. Radium isotopes

Elements having the same number of electrons but different mass numbers are called isotopes of the original element. Let us discuss the isotopes of Radium.

Radium has 33 isotopes based on their neutron numbers which are listed below

• ²⁰²Ra
• ²⁰³Ra
• ²⁰⁴Ra
• ²⁰⁵Ra
• ²⁰⁶Ra
• ²⁰⁷Ra
• ²⁰⁸Ra
• ²⁰⁹Ra
• ²¹⁰Ra
• ²¹¹Ra
• ²¹²Ra
• ²¹³Ra
• ²¹⁴Ra
• ²¹⁵Ra
• ²¹⁶Ra
• ²¹⁷Ra
• ²¹⁸Ra
• ²¹⁹Ra
• ²²⁰Ra
• ²²¹Ra
• ²²²Ra
• ²²³Ra
• ²²⁴Ra
• ²²⁵Ra
• ²²⁶Ra
• ²²⁷Ra
• ²²⁸Ra
• ²²⁹Ra
• ²³⁰Ra
• ²³¹Ra
• ²³²Ra
• ²³³Ra
• ²³⁴Ra

Here only stable isotopes are discussed below among those isotopes in the below section.

Isotope	Natural Abundance	Half-life	Emitting particles	No. of Neutron
223Ra	trace	11.43 days	α	137
224Ra	trace	3.63 days	α	138
225Ra	trace	14.9 days	β	139
226Ra	trace	1600 y	α	140
228Ra	trace	5.75 y	β	142

14. Radium electronic shell

The shell surrounding the nucleus as per principal quantum number and holding the electrons are called an electronic shell. Let us discuss the electronic shell of Radium.

The number of electronic shells of Radium around the nucleus is 86 which is s, p, d and f orbitals because to arrange the electrons, it need 1s,2s,2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 6s, 6p, and 7s orbitals. So, its electronic shell will be 2 2 6 2 6 10 2 6 10 14 2 6 10 2 6 2.

15. Radium electron configurations

According to Hund’s rule electrons are distributed to the respective orbitals which are known as electronic configurations. Let us discuss the electronic configuration of Radium.

The electronic configuration of Ra is 1s²2s²2p⁶3s²3p⁶ 3d¹⁰4s²4p⁶ 4d¹⁰ 4f¹⁴ 5s²5p⁶ 5d¹⁰6s²6p⁶7s² as it has 88 electrons. To fill all the 88 electrons according above two rules we need those electrons to need s, p, d, and f orbitals having the 1^st,2^nd, 3^rd, 4^th, 5^th, 6^th, and 7^th orbitals.

• Where the first number stands for the principal quantum number
• The letter is for orbital and the suffix number is the number of electrons.
• But many elements have more principal quantum numbers depending on the number of electrons.
• Kr has 86 electrons, so the remaining electrons are present after the noble gas configuration.
• So, it is denoted as [Kr]7s².

16. Radium energy of first ionization

The energy is required for the removal of the electrons from the valence orbital from its zero-oxidation state. Let us predict the first ionization energy of Radium.

The first ionization value for Ra is 509.3 KJ/mol because the electron was removed from the 7s orbital and the 7s orbital is subject to relativistic contraction, so the energy required to remove an electron from 7s is lesser than the 6s orbital of Ba.

17. Radium energy of second ionization

The energy is required for the removal of one electron from the available orbital from +1 oxidation state. Let us see the second ionization of Radium.

The energy required for 2nd ionization of Ra is 979 KJ/mol and this process the occurred from its 7s orbital, where the remaining electrons after 1^st ionization will be removed. So, when an electron is removed excited state it required higher energy than the previous one.

18. Radium energy of third ionization

Removal of third electrons from the outermost or pre-ultimate orbital of an element having a +2 oxidation state. Let us predict the third ionization of Radium.

The third ionization energy for Ra is 1837 KJ/mol because the third ionization occurs from the filled 6p orbital or we can say the third electron is removed from the 6p orbital. Due to the presence of 4d and 4f filled electrons they can shield the outermost orbital for the nucleus.

19. Radium oxidation states

During bond formation, the charge that appears on the element is called the oxidation state. Let us predict the oxidation state of Radium.

+2 oxidation state is the stable oxidation of Ra even for any alkaline Earth metal because they have only two electrons in their 6s orbital and after releasing those two electrons they gain the nearest noble gas configuration.

20. Radium CAS number

CAS number or CAS registration for any element to identify the element which is unique. Let us know the CAS number of Radium.

The CAS number of Radium is 7440-14-4 which is given by the chemical abstracts service.

21. Radium Chem Spider ID

Chem Spider ID is the particular number for a particular element given by the Royal Society of Science to identify by their character. Let us discuss it for Radium.

4511436 is the Chem Spider ID for Radium which is given by the RSC (royal society of chemistry). By using this number we can evaluate all the chemical data related to the Radium atom. Like the CAS number, it is also different for all elements.

22. Radium allotropic forms

Allotropes are the same chemical property but differ in physical properties. Let us discuss the allotropic form of Radium.

Ra has no allotropic form like other alkaline earth metals because they cannot show the catenation property like carbon elements. It is radioactive in nature so it cannot form any other allotropes.

23. Radium chemical classification

The elements are classified into some special class on the basis of chemical reactivity and nature. Let us know the chemical classification of Radium.

Radium is classified into the following categories,

• Radium is a radioactive substance
• Radium is an alkaline earth metal
• Radium is also classified as reactive based on the reaction tendency
• Radium is more ductile and carry electricity as per electrical conductance.

24. Radium state at room temperature

The state at which an element can exist at room temperature and standard pressure is called the physical state of that particular atom. Let us predict the state of Ra.

Radium exists in a solid state at room temperature because it has a crystal lattice of body center that it adopts in the hexagonal structure, where van der Waal’s force of attraction is so high. Also, the layers are present over one another, so it is soft in nature.

25. Is Radium paramagnetic?

Paramagnetism is the tendency of magnetization in the direction of the magnetic field. Let us see whether Radium is paramagnetic or not.

Radium is not paramagnetic in nature due to its radioactivity. But the presence of one paired electron in the 7s orbital makes it diamagnetic in nature.

Conclusion

Ra is alkaline earth metal of the 7^th period, so it has a 7s orbital. when it gets excited then it can fluorescent chemicals and cause radioluminescence. Radium is the one and only radioactive earth metal which can occur decay.