Potassium Mass Number

  1. Potassium 37 Mass Number
  2. Potassium Element Mass Number
  3. Potassium Mass Number Rounded
  4. Potassium-42 Mass Number
  5. Potassium Mass Number 41

Potassium is a chemical element with symbol K and atomic number 19. Classified as an alkali metal, Potassium is a solid at room temperature.

Answer 1:
  1. Potassium is the first element of the fourth period (row) in the periodic table. The atomic mass of potassium is 39.098 atomic mass units. It is denoted by the symbol ‘K’. The term potassium arises from a material called Potash.
  2. 39.0983 g.mol-1. Electronegativity according to Pauling. 0.86 g.cm-3 at 0 °C.

As you may know, atoms are composed of three different types of particles: protons, neutrons, which are found in the nucleus, and electrons which are found in the electron cloud around the nucleus. Protons and neutrons are responsible for most of the atomic mass. The atomic mass for protons and neutrons is the same. A proton has an atomic mass of 1 u (unified atomic mass). The mass of an electron is very small. Protons have a positive (+) charge, neutrons have no charge --they are neutral. Electrons have a negative charge (-). The number of protons and electrons is the same in a neutral (uncharged) atom.

How can you find out how many protons (= electrons) an element has? You look at the periodic table. In this table the elements are listed according to their atomic number. Hydrogen is the first element with an atomic number of 1. Now, the atomic number is also the number of protons in an element. It is always constant. (e.g., H=1, K=19, Ur=92). So if you look for potassium (symbol K in the periodic table), you will find that it has the atomic number of 19. This tells you that potassium has 19 protons and - since the number of protons is the same as the number of electrons- also 19 electrons.

To find out the number of neutrons you have to look at the atomic mass or weight of the element. This can also be found in the periodic table. It is the number under the element symbol. For potassium it is about 39. This means that the atomic weight is 39 for both protons and neutrons. Since we know that the number of protons is 19 we can calculate the number of neutrons (39 19) as 20.

Things can be a bit more complicated however. The same element may contain varying numbers of neutrons; elements that have the same number of protons but different numbers of neurons are called isotopes. Oxygen, with atomic number of 8, for example, can have 8, 9, or 10 neutrons. (The atomic number for oxygen is 8, and the atomic mass is 15.9994).

MassPotassium Mass Number

If you read the atomic weight for potassium it reads 39.098. This tells you that there must be some other isotopes for potassium. In fact, natural potassium has three isotopes with 20, 21 and 22 neutrons with the abundance of 93.26 %, 0.01 % and 6.73 % respectively.

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Potassium is an alkali metal and was obtained in pure elemental form in 1807 by Hymphry Davy. It is a biologically essential element and also has various industrial applications, including fertilizers, pesticides, explosives etc.

Discovery and History

Potassium was discovered from the ashes of plants and its name was derived from potash (plant ashes). In early days, potassium was extracted by placing ashes of burnt tree in a pot along with water. the mixture was heated and the solution by evaporated to obtain potash (potassium). It was first obtained in pure form by Humphry Davy (1807), through the process of electrolysis. The symbol of potassium is K and is derived from kali (alkali), which is derived from Arabic work for plant ashes (al-qalyah) [1].


Periodic Table ClassificationGroup 1
Period 4
State at 20CSolid
Electron Configuration[Ar] 4s1
Electron Number19
Proton Number19
Electron Shell2, 8, 8, 1
Density0.86 g.cm-3 at 20°C
Atomic number19
Atomic Mass39.10 g.mol -1
Electronegativity according to Pauling0.82


Potassium occurs in nature in the form of ionic salts. In ratio of abundance, it is the 20th most abundant element in the solar system and 17th most abundant on the earth (makes around 2.6% of weight of the earth’s crust). It is also found in dissolved form in sea water and constitute about 0.04% potassium by weight [2]. It has a low first ionization energy (418.8 kL/mol). Potassium is also present in Supernovae environment and produced through explosive oxygen-burning process. In human body, potassium constitutes about 0.2% by mass and is about the 8th most abundant element of human biological system. It is a major component of variety of proteins and enzymes. Potassium is also present in fruits (high concentrations in bananas, avocadoes), vegetables (potatoes, tomatoes, beet green, white beans), fish and meat.

Physical Characteristics

Potassium is silvery-white, soft metal with second least density (0.89 g/cm3). At standard conditions, potassium can be cut with a knife. Potassium undergoes tarnishing when exposed to air and oxygen. Potassium can float on water. It has a boiling point of 770 °C and melting point of 63 °C. It belongs to Group 1 (1A) of periodic table. Potassium gives a vigorous reaction with water (forming potassium hydroxide) and burns with a pale violet color.

Chemical Characteristics

Potassium 37 Mass Number

Potassium has one valence electron, that is readily lost to acquire a positive charge. Potassium is one of the alkali metals and it can combine with anions to from salts. It is very reactive and is rapidly oxidized when exposed to air forming potassium peroxide. Potassium gives a vigorous reaction with water (forming potassium hydroxide) and burns with a pale violet color. Potassium does not react with hydrocarbons (kerosene or mineral oil). Potassium is a powerful reducing agent and is highly stable in its oxidized form [3]. With water, potassium forms a strong alkali (KOH). The compounds of potassium are highly ionic and have high solubility.

Potassium Element Mass Number

Significance and Uses

  • It is widely used in fertilizers. It is the largest industrial usage of potassium and about 90% of potassium produced in the world is utilized in the production of various fertilizers.
  • It is a commonly used food additive and is main component of baking powder and silvering mirrors.
  • Potassium chromate is a widely used pigment and is part of dyes, inks, stains etc.
  • Potassium is used in leather tanning industries.
  • It is used to make fireworks, matches and explosives (Potassium chlorate).
  • Potassium carbonate, usually termed as potash is widely used in the manufacturing of soap, glass, fluorescent lamps, fire extinguishers, and color TV.
  • Potassium bromide is used as a sedative.
  • It is used as a heat exchange material, in nuclear power generating plants.
  • Potassium is also used in making insecticides and pesticides.

Health Hazards

Potassium is an essential nutrient and human body requires a balanced supply (about 3.3 gram daily) of potassium. Deficiency of potassium can lead to hypokalemia and hypertension [4]. The reaction of potassium with water is highly exothermic and splashes can lead to skin burns and damage. It reacts explosively with sulphur acid, so special care is required during handling of potassium.

Isotopes of Potassium

There are about two dozen isotopes of potassium, and three of them occur naturally (39K, 40K and 41K). 40K is the radioactive isotope. Adobe audition vst3. It is present in human body in great abundance and around 4,400 nuclei of 40K decay per second occur in an average human body. 40K provides the largest source of natural radioactivity and used widely for rock dating. 39K is the most common isotope and constitute around 93.3 % of potassium isotopes [5].


[1] http://www.chemistryexplained.com/elements/L-P/Potassium.html

[2] Webb, D. A. (April 1939). “The Sodium and Potassium Content of Sea Water” (PDF). The Journal of Experimental Biology (2): 183.

Potassium Mass Number Rounded

[3] Dye, J. L. (1979). “Compounds of Alkali Metal Anions”. Angewandte Chemie International Edition. 18 (8): 587–598. doi:10.1002/anie.197905871

Potassium-42 Mass Number

[4]. Whelton PK, He J, Cutler JA, Brancati FL, Appel LJ, Follmann D, Klag MJ (1997). “Effects of oral potassium on blood pressure. Meta-analysis of randomized controlled clinical trials”. JAMA. 277 (20): 1624–32. doi:10.1001/jama.1997.03540440058033. PMID9168293.

[5] “Radiation and Radioactive Decay. Radioactive Human Body”. Harvard Natural Sciences Lecture Demonstrations. Retrieved July 2, 2016

Potassium Mass Number 41

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