Potassium | History, Uses, Facts, Physical & Chemical Characteristics (2024)

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].

Potassium

Periodic Table ClassificationGroup 1
Period 4
State at 20CSolid
ColorSilvery-gray
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

Occurrence

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 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.

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. 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].

REFERENCES

[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.

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

[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

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Potassium | History, Uses, Facts, Physical & Chemical Characteristics (2024)

FAQs

Potassium | History, Uses, Facts, Physical & Chemical Characteristics? ›

Potassium metal is soft and white with a silvery lustre, has a low melting point, and is a good conductor of heat and electricity. Potassium imparts a lavender colour to a flame, and its vapour is green. It is the seventh most abundant element in Earth's crust, constituting 2.6 percent of its mass.

What are 5 facts about potassium? ›

Data Zone
Classification:Potassium is an alkali metal
Color:silvery-white
Atomic weight:39.0983
State:solid
Melting point:63.4 oC, 336.5 K
7 more rows

What are 5 uses of potassium? ›

Industrial applications for potassium include soaps, detergents, gold mining, dyes, glass production, gunpowder, and batteries.

What is the physical function of potassium? ›

Potassium is a metal element found in group one of the periodic table and an important mineral nutrient in the human diet. We need potassium because its roles in the human body include fluid regulation, muscle contraction, and regulation of nerve signals.

Is potassium a chemical or physical change? ›

Potassium is a chemical element; it has symbol K (from Neo-Latin kalium) and atomic number 19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure.

What are 3 characteristics of potassium? ›

Potassium metal is soft and white with a silvery lustre, has a low melting point, and is a good conductor of heat and electricity.

What are 3 benefits of potassium? ›

Potassium has many important functions: It allows the nerves to respond to stimulation and muscles to contract (tighten), including those in the heart. It reduces the effect of sodium (present in table salt) on blood pressure. It helps move nutrients into cells, and waste products out of cells.

What is potassium best used for? ›

The most important use of potassium is to treat the symptoms of hypokalemia (low potassium), which include weakness, lack of energy, muscle cramps, stomach disturbances, an irregular heartbeat, and an abnormal EKG (electrocardiogram, a test that measures heart function).

What are the 3 things potassium is essential for? ›

It is a type of electrolyte. It helps your nerves to function and muscles to contract. It helps your heartbeat stay regular. It also helps move nutrients into cells and waste products out of cells.

What is potassium in everyday use? ›

Potassium plays a role in the transmission of nerve signals, muscle contractions, fluid balance, and various chemical reactions. Potassium is most commonly used for treating and preventing low potassium levels, treating high blood pressure, and preventing stroke.

What are the 10 signs of high potassium? ›

Symptoms of High Potassium
  • Stomach pain.
  • Diarrhea.
  • Fatigue.
  • Chest pain.
  • Irregular heartbeat that may feel fast or like a fluttering sensation.
  • Muscle weakness.
  • Numbness or paralysis in your arms or legs.
  • Nausea or vomiting.
Mar 19, 2024

Is potassium good for skin? ›

Potassium helps regulate the water storage in your body and prevents moisture loss, and in turn keeps your skin healthy and glowing.

What organ is most affected by potassium? ›

Your Heart and Other Muscles

Because it's a muscle, your heart needs potassium. It helps cells send the right electrical signals so that the heart pumps correctly. Having too much potassium in the body can alter the heart's rhythm.

What are the 5 physical properties of potassium? ›

Chemical properties of potassium - Health effects of potassium - Environmental effects of potassium
Atomic number19
Density0.86 g.cm -3 at 0 °C
Melting point63.2 °C
Boiling point760 °C
Vanderwaals radius0.235 nm
7 more rows

Is potassium flammable? ›

ICSC 0716 - POTASSIUM. Highly flammable. Many reactions may cause fire or explosion. Gives off irritating or toxic fumes (or gases) in a fire.

What is 5 potassium? ›

Potassium is a chemical that is critical to the function of nerve and muscle cells, including those in your heart. Your blood potassium level is normally 3.6 to 5.2 millimoles per liter (mmol/L). Having a blood potassium level higher than 6.0 mmol/L can be dangerous and usually requires immediate treatment.

What are the top 5 foods for potassium? ›

Below is a list of 10 high-potassium foods:
  • Swiss chard, 1 cup cooked (960 mg)
  • Spinach, 1 cup cooked (840 mg)
  • Avocado, 1 cup (708 mg)
  • Sweet potato, medium (700 mg)
  • Bok choy, 1 cup cooked (630 mg)
  • Potato, medium (610 mg)
  • White beans, 1/2 cup (600 mg)
  • Beets, 1 cup (520 mg)
Sep 19, 2016

What is potassium in the body fun facts? ›

Potassium is present in all body tissues and is required for normal cell function because of its role in maintaining intracellular fluid volume and transmembrane electrochemical gradients [1,2]. Potassium has a strong relationship with sodium, the main regulator of extracellular fluid volume, including plasma volume.

What are some fun facts about potassium 40? ›

Potassium-40 is the largest source of natural radioactivity in animals including humans. A 70 kg human body contains about 140 g of potassium, hence about 140g × 0.0117% ≈ 16.4 mg of 40K; whose decay produces about 3850 to 4300 disintegrations per second (becquerel) continuously throughout the life of the person.

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