Rubidium (Rb) – Periodic Table [Element Information & More]

rubidium element periodic table

Rubidium element (Rb) is in group 1 and period 5 of a periodic table. Rubidium is in the s-block and it is classified as an alkali metal on the periodic table.

There is a lot more information related to rubidium which is mentioned in the Information Table given below.

So let’s dive right into it!

Table of contents

Rubidium Element (Information Table)

The important data related to rubidium element is given in the table below.

Appearance of rubidiumGrey white
Atomic number of rubidium37
Symbol of rubidiumRb
Atomic mass of rubidium85.468 u
Protons, Neutrons & Electrons in rubidiumProtons: 37, Neutrons: 48, Electrons: 37
State of rubidium (at STP)Solid
Group number of rubidium in periodic table1
Period number of rubidium in periodic table5
Block of rubidium in periodic tables-block
Category of rubidiumAlkali metals
Bohr model or Electrons per shell or Electrons arrangement in rubidium2, 8, 18, 8, 1
Electron configuration of rubidium[Kr] 5s1
Orbital diagram of rubidiumorbital diagram of rubidium
Valence electrons in rubidium1
Electronegativity of rubidium (on pauling scale)0.82
Atomic radius of rubidium (van der Waals radius)303 picometers
Density of rubidium1.53 g/cm3
1st ionization energy of rubidium4.177 eV
Main isotope of rubidium85Rb, 87Rb
Melting point of rubidium312.4 K or 39.3 °C or 102.7 °F
Boiling point of rubidium961 K or 688 °C or 1270 °F
Crystal structure of rubidiumBody Centered Cubic (BCC)
Discovery of rubidiumBy Robert Bunsen and Gustav Kirchhoff (in 1861)

Also see: Interactive Periodic Table (It has rotating bohr models as well as many other details of all the 118 elements in a single periodic table).

Rubidium element in Periodic table

The Rubidium element (Ru) has the atomic number 37 and is located in group 1 and period 5. Rubidium is in solid state at STP and it is classified as an alkali metal on the periodic table.

Click on above elements in the periodic table to see their information.

Facts about rubidium

Here are a few interesting facts about rubidium element.

  1. The name “Rubidium” came from the Latin word “rubidus” (which means deep red).
  2. Rubidium is the second most electropositive element.
  3. Rubidium is the 23rd most abundant element found from the earth’s crust.
  4. The amount of rubidium in the seawater is approximately 125 µg/L.
  5. The density of rubidium is 1.5 times the density of water.

Properties of rubidium

Here is a list of some physical properties and chemical properties of rubidium.

Physical properties of rubidium

  • Rubidium is a soft metal and it has a gray-white appearance.
  • The melting point of rubidium is 39.3 °C, which is slightly higher than our body temperature (our body temperature is 37 °C).
  • The boiling point of rubidium is 688 °C.
  • Rubidium has many isotopes, but the stable isotopes that are found from the earth’s crust are 85Rb and 87Rb.

Chemical properties of rubidium

  • Rubidium is a reactive metal and it is not found in its pure form. It is always found as a compound with other elements in the earth’s crust.
  • The rubidium metal gives a red-violet color in flame test.
  • Rubidium reacts with oxygen to form a number of oxides (like Rb2O, Rb6O, Rb9O2, etc).
  • Rubidium metal reacts violently with water and releases heat. This heat can even ignite the hydrogen gas which is released during the reaction.

Uses of rubidium

Here are some uses of the rubidium element.

  • The compounds of rubidium are used in fireworks to produce the red-violet color.
  • Rubidium is a highly reactive metal and hence it is mostly used in research work in chemistry.

External resources:

  1. It’s Elemental – The Element Rubidium. (n.d.). It’s Elemental – the Element Rubidium.
  2. Georgescu, I. (2015, November 20). Rubidium round-the-clock. Nature Chemistry, 7(12), 1034–1034.
  3. Simmons, E. C. (n.d.). Rubidium: Element and geochemistry. Encyclopedia of Earth Science, 555–556.
  4. Possolo, et al. (2018, January 4). Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report). Pure and Applied Chemistry, 90(2), 395–424.
  5. Emsley, J. (2011). Nature’s Building Blocks: An A-Z Guide to the Elements. United Kingdom: OUP Oxford.
  6. Haynes, W. M. (Ed.). (2014, June 4). CRC Handbook of Chemistry and Physics.
  7. Electronic structure of the elements. (2000, March). The European Physical Journal C, 15(1–4), 78–79.
  8. Rubidium – Element information, properties and uses | Periodic Table. (n.d.). Rubidium – Element Information, Properties and Uses | Periodic Table.
  9. P. (n.d.). Rubidium | Rb (Element) – PubChem. Rubidium | Rb (Element) – PubChem.
  10. It’s Elemental – The Element Rubidium. (n.d.). It’s Elemental – the Element Rubidium.
  11. James A. M. & Lord M. P. (1992). Macmillan’s chemical and physical data. Macmillan.
  12. Bedford, et al. (1996, April 1). Recommended values of temperature on the International Temperature Scale of 1990 for a selected set of secondary reference points. Metrologia, 33(2), 133–154.
  13. Allred, A. (1961, June). Electronegativity values from thermochemical data. Journal of Inorganic and Nuclear Chemistry, 17(3–4), 215–221.
  14. Periodic Table of Elements: Los Alamos National Laboratory. (n.d.). Periodic Table of Elements: Los Alamos National Laboratory.
  15. Cesium and Rubidium Statistics and Information | U.S. Geological Survey. (n.d.). Cesium and Rubidium Statistics and Information | U.S. Geological Survey.

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