What Is Rubidium Definition Atomic Structure Properties and Uses
Rubidium is a silvery-white and extremely soft metal and amongst the most highly reactive elements on the periodic table. Rubidium has a density of about one and a half times that of water and is solid at room temperature, although it melts if it is just a bit warmer. It ignites spontaneously when it comes in contact with air and reacts violently with water and even with ice at -100 C, setting fire to the hydrogen that is liberated. Amongst all the other alkali metals, it forms amalgams with the element mercury. It alloys with gold, sodium, potassium and caesium. Its flame is yellowish-violet in colour. In this article, we will learn about Rb element in detail including rubidium element uses, structure, and chemical properties.
What is Rubidium?
Rubidium is a chemical element having the symbol Rb and the atomic number 37. It is an extremely soft, silvery-white coloured metal in the alkali metal group. The rubidium metal shares similarities to the potassium metal and the caesium metal when it comes to the physical appearance, softness and conductivity. It cannot be stored under atmospheric oxygen since a highly exothermic reaction would ensue, sometimes even resulting in the metal catching fire. It is the first alkali metal in the group having a density higher than water, hence it sinks, unlike the other metals that are above it in the group.
Rubidium Structure
The structure of rubidium is shown as below:
Let Us Now Look at the Chemical Properties of Rubidium
Chemical Properties of Rubidium
Rubidium Uses
Rubidium has the following uses:
Rubidium compounds are used in the fireworks for giving them a purple colour.
Rubidium is used in the thermoelectric generator by using the magnetohydrodynamic principle, wherein the hot rubidium ions are allowed to pass through a magnetic field.
Vaporized rubidium, which is 87Rb, is one of the most commonly used atomic species for the laser cooling and the Bose-Einstein condensation.
For cold-atom applications that require tunable interactions, 85Rb is preferable because of its rich Feshbach spectrum.
Rubidium is also used for polarizing Helium-3 gas.
The resonant element in the atomic clocks utilizes the hyperfine structure of the rubidium's energy levels, and hence, rubidium is used for high-precision timing.
Rubidium is used as the main component of secondary frequency references or rubidium oscillators in the cell site transmitters and several other electronic transmitting, networking, and testing equipment.
It is used as a working fluid in vapour turbines, as a getter in vacuum tubes, and as a component of the photocell.
Rubidium is used as an ingredient in a special type of glass, production of superoxide by burning in oxygen, the study of potassium ion channels in biology, and as the vapour in the atomic magnetometers.
Rubidium-82 is used for the positron emission tomography.
FAQs on Rubidium Element in Chemistry Properties and Uses
1. What is rubidium in chemistry?
Rubidium is a chemical element with symbol Rb and atomic number 37, belonging to the alkali metals in Group 1 of the periodic table. It is a soft, silvery-white metal that is highly reactive, especially with water and oxygen. Key properties of rubidium include:
- Electronic configuration: [Kr] 5s1
- Common oxidation state: +1
- Low density and low melting point (about 39 °C)
2. What group and period is rubidium in?
Rubidium is in Group 1 and Period 5 of the periodic table. As a Group 1 element, it is classified as an alkali metal. Its position explains its properties:
- One valence electron in the 5s orbital
- Strong tendency to form Rb+ ions
- High chemical reactivity
3. What is the electron configuration of rubidium?
The electron configuration of rubidium is [Kr] 5s1. In full form, it is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1. This means:
- Rubidium has one valence electron in the outermost shell.
- It easily loses this electron to form Rb+.
- This accounts for its strong reducing behavior and high reactivity.
4. Why is rubidium so reactive?
Rubidium is highly reactive because it has a single valence electron that is easily lost to form Rb+. The outer 5s electron is far from the nucleus and weakly attracted due to shielding by inner shells. As a result:
- It has low ionization energy.
- It reacts vigorously with water and oxygen.
- Its reactivity increases down Group 1.
5. How does rubidium react with water?
Rubidium reacts violently with water to form rubidium hydroxide and hydrogen gas. The balanced chemical equation is:
2Rb(s) + 2H2O(l) → 2RbOH(aq) + H2(g)
- The reaction is highly exothermic.
- Hydrogen gas may ignite due to released heat.
- The solution formed is strongly alkaline because of RbOH.
6. What is the valency and oxidation state of rubidium?
Rubidium has a valency of 1 and a common oxidation state of +1. It loses one electron to achieve the stable noble gas configuration of krypton. As a result:
- It forms ionic compounds such as RbCl and Rb2SO4.
- The rubidium ion is written as Rb+.
- It does not commonly show multiple oxidation states.
7. What are the common compounds of rubidium?
Common compounds of rubidium include ionic salts formed with nonmetals and polyatomic ions. Important examples are:
- RbCl (rubidium chloride)
- RbOH (rubidium hydroxide)
- Rb2CO3 (rubidium carbonate)
- RbNO3 (rubidium nitrate)
8. How is rubidium extracted or obtained?
Rubidium is obtained mainly from minerals such as lepidolite and pollucite and isolated by electrolysis or chemical reduction. The general steps include:
- Extraction from lithium-rich ores.
- Conversion to rubidium salts such as RbCl.
- Reduction with a stronger reducing agent or electrolysis of molten salts.
9. What are the uses of rubidium in chemistry and industry?
Rubidium is mainly used in atomic clocks, research, and specialized electronic applications. Key uses include:
- Rubidium atomic clocks for precise time measurement.
- Photoelectric cells and vacuum tubes.
- Biomedical research as a tracer (Rb+ behaves like K+ in cells).
10. What is the difference between rubidium and potassium?
Rubidium and potassium are both alkali metals, but rubidium is more reactive and has a larger atomic size. The main differences are:
- Atomic number: potassium = 19, rubidium = 37.
- Electron configuration: K = [Ar] 4s1, Rb = [Kr] 5s1.
- Rubidium has lower ionization energy and reacts more violently with water.
