This article will describe potassium in terms of physics and chemistry. The first of these sciences studies the mechanical and external properties of substances. And the second - their interaction with each other - is chemistry. Potassium is the nineteenth element in the periodic table. It belongs to alkali metals. In this article, the electronic formula of potassium, and its behavior with other substances, etc. will be considered. This is one of the most active metals. The science that studies this and other elements is chemistry. Grade 8 provides for the study of inorganic substances and their properties. Therefore, this article will be useful to students. So, let's begin.
Physics Characterization of Potassium
This is a simple substance, which under normal conditions is in a solid state of aggregation. The melting point is sixty-three degrees Celsius. This metal boils when the temperature reaches seven hundred sixty-one degrees Celsius. The substance in question has a silver-white color. It has a metallic sheen.
The density of potassium is eighty-six hundredths of a gram per centimeter cubic. This is a very light metal. The potassium formula is very simple - it does not form molecules. This substance consists of atoms that are located close to each other and have a crystal lattice. The atomic mass of potassium is thirty-nine grams per mole. Its hardness is very low - it can be easily cut with a knife, like cheese.
Potassium and Chemistry
To begin with, potassium is a chemical element that has a very high chemical activity. You canβt even store it in the open air, as it immediately begins to react with the substances surrounding it. Potassium is a chemical element that belongs to the first group and the fourth period of the periodic table. It has all the properties that are characteristic of metals.
Interactions with simple substances
These include: oxygen, nitrogen, sulfur, phosphorus, halogens (iodine, fluorine, chlorine, bromine). In order, we consider the interaction of potassium with each of them. The interaction with oxygen is called oxidation. During this chemical reaction, potassium and oxygen are consumed in a molar ratio of four parts to one, resulting in the formation of the oxide of the metal in question in the amount of two parts. This interaction can be expressed using the following reaction equation: 4K + O2 = 2K2O. When burning potassium, a bright purple flame can be observed .
Therefore, this reaction is considered to be qualitative for the determination of potassium. Reactions with halogens are called according to the names of these chemical elements: iodination, fluorination, chlorination, bromination. These interactions can be called addition reactions, since the atoms of two different substances are combined into one. An example of such a process is the reaction between potassium and chlorine, resulting in the formation of chloride of the metal in question. To carry out this interaction, it is necessary to take these two components - two moles of the first and one of the second. As a result, two moles of potassium compound are formed. This reaction is expressed by the following equation: 2K + Π2 = 2Π. With nitrogen, potassium can give compounds when burning outdoors. During this reaction, the considered metal and nitrogen are consumed in a molar ratio of six parts to one; as a result of this interaction, two parts of potassium nitride are formed. This can be shown in the form of the following equation: 6K + N2 = 2K3N. This compound is a green-black crystals. The metal in question reacts with phosphorus in the same way. If we take three moles of potassium and one mole of phosphorus, we get one mole of phosphide. This chemical interaction can be written in the form of the following reaction equation: 3K + P = K3P. In addition, potassium is able to react with hydrogen to form a hydride. As an example, the following equation can be given: 2K + H2 = 2KN. All addition reactions occur only in the presence of high temperatures.
Interaction with complex substances
The characterization of potassium from the point of view of chemistry provides for consideration of this topic. Complex substances potassium is capable of reacting with include water, acids, salts, and oxides. With all of them, the metal in question reacts differently.
Potassium and water
This chemical element reacts violently with it. In this case, hydroxide is formed, as well as hydrogen. If we take two moles of potassium and water, we get the same amount of potassium hydroxide and one mole of hydrogen. This chemical interaction can be expressed using the following equation: 2K + 2H2O = 2KOH = H2.
Acid Reactions
Since potassium is an active metal, it easily displaces hydrogen atoms from their compounds. An example would be the reaction that occurs between the substance in question and hydrochloric acid. To carry it out, you need to take two moles of potassium, as well as acid in the same amount. As a result, potassium chloride is formed - two moles and hydrogen - one mole. This process can be written with the following equation: 2K + 2NSI = 2KSI + H2.
Potassium and oxides
The metal in question reacts with this group of inorganic substances only with significant heating. If the atom of the metal that is part of the oxide is more passive than the one we are talking about in this article, in essence, an exchange reaction occurs. For example, if you take two moles of potassium and one mole of cuprum oxide, as a result of their interaction, you can get one mole of oxide of the chemical element in question and pure cuprum. This can be shown in the form of such an equation: 2K + CuO = K2O + Cu. This is where the strong reducing properties of potassium appear.
Interaction with the grounds
Potassium is able to react with metal hydroxides, which are to the right of it in the electrochemical series of activity. In this case, its reducing properties also appear. For example, if we take two moles of potassium and one mole of barium hydroxide, then as a result of the substitution reaction, we get substances such as two moles of potassium hydroxide and pure barium (one mole) - it will precipitate. The presented chemical interaction can be displayed in the form of the following equation: 2K + Ba (OH) 2 = 2KOH + Ba.
Reactions with Salts
In this case, potassium still shows its properties as a strong reducing agent. Replacing the atoms of chemically more passive elements, it allows you to get a pure metal. For example, if two moles of three moles of potassium are added to aluminum chloride in the amount of three moles of potassium chloride and two moles of aluminum as a result of this reaction. Express this process using the equation as follows: 3K + 2AIC_3 = 3KS_2 + 2AI.
Fats Reactions
If you add potassium to any organic substance of this group, it will also displace one of the hydrogen atoms. For example, when stearin is mixed with the metal in question, potassium stearate and hydrogen are formed. The resulting substance is used to make liquid soap. This completes the characterization of potassium and its interactions with other substances.
The use of potassium and its compounds
Like all metals, this article is required for many industrial processes. The main use of potassium occurs in the chemical industry. Due to its high chemical activity, pronounced alkaline metal and reducing properties, it is used as a reagent for many interactions and to obtain a variety of substances. In addition, potassium alloys are used as coolants in nuclear reactors. Also considered in this article, metal finds its application in electrical engineering. In addition to all of the above, it is one of the main components of fertilizers for plants. In addition, its compounds are used in a wide variety of industries. Thus, potassium cyanide is used in gold mining, which serves as a reagent for the separation of valuable metals from ores. In the manufacture of glass, potassium carbonate is used. The phosphates of the chemical element in question are components of all kinds of cleaning agents and powders. In matches there is a chlorate of this metal. In the manufacture of films for old cameras, the bromide of the element in question was used. As you already know, it is possible to obtain it by brominating potassium in a condition of high temperature. In medicine, the chloride of this chemical element is used. In soap making, stearate and other derivatives from fats.
Getting the metal in question
Nowadays, potassium is extracted in laboratories in two main ways. The first is its reduction from hydroxide with sodium, which is chemically even more active than potassium. And the second is getting it from chloride, also with the help of sodium. If you add as much sodium to one mole of potassium hydroxide, one mole of sodium alkali and pure potassium are formed. The equation of this reaction is as follows: KOH + Na = NaOH + K. For the second type of reaction, the chloride of the metal in question and sodium must be mixed in equal molar proportions. As a result of this, substances such as table salt and potassium are formed in the same ratio. This chemical interaction can be expressed using the following reaction equation: KCI + Na = NaCl + K.
Potassium structure
The atom of this chemical element, like everyone else, consists of a nucleus that contains protons and neutrons, as well as electrons that revolve around it. The number of electrons is always equal to the number of protons that are inside the nucleus. If any electron is disconnected or attached to the atom, then it already ceases to be neutral and turns into an ion. They are of two types: cations and anions. The former have a positive charge, and the latter have a negative charge. If an electron has joined an atom, then it turns into an anion; if any of the electrons leaves its orbit, the neutral atom becomes a cation. Since the serial number of potassium, according to the periodic table, is nineteen, there are as many protons in the nucleus of a given chemical element. Therefore, we can conclude that there are nineteen electrons around the nucleus. The number of protons that are contained in the structure of an atom can be determined by subtracting the serial number of the chemical element from the atomic mass. So we can conclude that there are twenty protons in the potassium nucleus. Since the metal considered in this article belongs to the fourth period, it has four orbits on which electrons are uniformly located, which are constantly in motion. The scheme of potassium is as follows: two electrons are located on the first orbit, eight on the second; as well as in the third, in the last, fourth, orbit, only one electron rotates. This explains the high level of chemical activity of this metal - its last orbit is not completely filled, so it seeks to connect with any other atoms, as a result of which their electrons in the last orbits will become common.
Where can I find this element in nature?
Since it has an extremely high chemical activity, it is not found anywhere on the planet in its pure form. It can only be seen in a variety of compounds. Mass fraction of potassium in the earth's crust is 2.4 percent. The most common minerals that include potassium are salvinite and carnallite. The first has the following chemical formula: NaCl β’ KCl. It has a motley color and consists of many crystals of various colors. Depending on the ratio of potassium chloride to sodium, as well as on the presence of impurities, it may contain red, blue, pink, orange components. The second mineral - carnallite - looks like transparent, pale blue, light pink or pale yellow crystals. Its chemical formula is as follows: KCl β’ MgCl2 β’ 6H2O. It is crystalline hydrate.
The role of potassium in the body, symptoms of deficiency and excess
Together with sodium, it maintains the water-salt balance of the cell. He also participates in the transmission between the membranes of the nerve impulse. In addition, it regulates the acid-base balance in the cell and throughout the body as a whole. He takes part in metabolic processes, counteracts the occurrence of edema, and is part of the cytoplasm - about fifty percent of it - the salt of the metal in question. The main signs that the body lacks potassium are swelling, the occurrence of a disease such as dropsy, irritability and disturbances in the functioning of the nervous system, inhibition of the reaction and memory impairment.
In addition, an insufficient amount of this trace element negatively affects the cardiovascular and muscle systems. A lack of potassium for a very long time can provoke a heart attack or stroke. But due to an excess of potassium, an ulcer of the small intestine can develop in the body. To balance your diet in such a way as to get a normal amount of potassium, you need to know what foods it contains.
High micronutrient foods
First of all, these are nuts, such as cashews, walnuts, hazelnuts, peanuts, almonds. Also, a large number of it is in the potatoes. In addition, potassium is found in dried fruits, such as raisins, dried apricots, prunes. Pine nuts are also rich in this element. Also, its high concentration is observed in legumes: beans, peas, lentils. Sea kale is also rich in this chemical element. Other products containing this element in large quantities are green tea and cocoa. In addition, it is found in high concentration in many fruits, such as avocados, bananas, peaches, oranges, grapefruits, apples. Many cereals are rich in the trace element in question. This is primarily barley, as well as wheat and buckwheat. Parsley and Brussels sprouts also have a lot of potassium. In addition, it is found in carrots and melons. Onions and garlic have a considerable amount of the chemical element in question. Chicken eggs, milk and cheese are also high in potassium. The daily rate of this chemical element for an average person is from three to five grams.
Conclusion
After reading this article, we can conclude that potassium is an extremely important chemical element. It is necessary for the synthesis of many compounds in the chemical industry. In addition, it is used in many other industries. It is also very important for the human body, therefore, it must regularly and in the required amount go there with food.