Where more than one isotope exists, the value given is the abundance weighted average.Ītoms of the same element with different numbers of neutrons. This is approximately the sum of the number of protons and neutrons in the nucleus. The mass of an atom relative to that of carbon-12. The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.ĭensity is the mass of a substance that would fill 1 cm 3 at room temperature. The temperature at which the liquid–gas phase change occurs. The temperature at which the solid–liquid phase change occurs. The arrangements of electrons above the last (closed shell) noble gas. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f). The atomic number of each element increases by one, reading from left to right.Įlements are organised into blocks by the orbital type in which the outer electrons are found. Members of a group typically have similar properties and electron configurations in their outer shell.Ī horizontal row in the periodic table. Your browser does not support the audio element.A vertical column in the periodic table. Some good sources of potassium in our diet include bananas, avocados, nuts, chocolate, parsley, and potatoes.It is used in fire extinguishers, baking powders, and antacids. Potassium bicarbonate is the chemical name for baking soda.A higher concentration can taste bitter or salty. A small amount of potassium can taste sweet. The USDA recommends that adults consume 4.7 grams of potassium each day.Potassium chloride (KCl) is sometimes used as a substitute for table salt.The majority (93%) of potassium found in nature is K-39. There are three isotopes of potassium that occur naturally: K-39, 40, and 41. The K symbol for the element comes from the Latin word "kalium", which means potash. Potassium gets its name from the salt potash from which potassium was first isolated. He used electricity to separate the element from the salt potash. Potassium was first isolated by English chemist Sir Humphry Davy in 1807. It is about the eighth most abundant element in the human body by weight. It is used in muscle contraction, fluid and pH balance, bone health, and helps to prevent kidney stones. Potassium also plays a vital role in our bodies. Industrial applications for potassium include soaps, detergents, gold mining, dyes, glass production, gunpowder, and batteries. This is because potassium is important for plant growth. The largest use of potassium is potassium chloride (KCl) which is used to make fertilizers. It can also be found in ocean water where it is also about the eighth most abundant element. Making up about 2.1% of the weight of the Earth's crust, potassium is the eighth most abundant element in the crust. Most minerals that contain potassium are referred to as potash. Instead it is found in various minerals such as sylvite, carnallite, langbeinite, and kainite. It also reacts with many other elements and substances such as oxygen, acids, sulfur, fluorine, and nitrogen.īecause potassium reacts so readily with water, it is not found in its elemental form in nature. It reacts violently when coming into contact with water, producing heat and hydrogen gas. It is so light that it can float in water.Ĭhemically, potassium is a very active metal. Potassium also has a very low density and is the second least dense metal after lithium. When it burns, it produces a pale purple colored flame. Potassium has a very low melting point such that even a candle can cause it to melt. When cut, the exposed metal tarnishes quickly and forms a dull oxide coating. It is so soft that it can be easily cut with a knife. Under standard conditions potassium is a soft silvery-white metal. Potassium is considered chemically similar to sodium, the alkali metal above it on the periodic table. Potassium atoms have 19 electrons and 19 protons with one valence electron in the outer shell. Potassium is the fourth element in the first column of the periodic table.
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