What is this in chemistry?

In chemistry, the bivalent is an older term for wild, which means atom or ion with valence of two. Valence refers to the number of covalent links that atom or ion can form with other atoms. Covalent bonds consist of electrons sharing on the farthest valence shells or in orbit atom, so that the bivalent atom or ion has two valence electrons by definition to create links. In many biological systems, including human metabolism, it can be visualized as a orbiting atom in a number of shells, each of which each of which can be visualized as a certain number of electrons, each of which can only have a certain number of electrons that can only hold a certain number of electrons that can only maintain a certain number of electrons. Negative and positive charges, respectively. Shells closer to the core are filled first. When atoms react to each other, they tend to be SPOJIT in such a way to fill their farthest or valence, the shell of the electrons. In almost any case, the full valence shell consists of an eight -electron - the same valence configuration as the elements in the Noble Gas family, the last vertical column in the periodic table of the elements. The tendency of atoms to obtain or lose electrons from other atoms to achieve this stable valence octet is called the rule of octet.

bivalent elements have two valence electrons, so the easiest way to achieve a full octare valence shell is to lose these two outer electrons and instead leave the shell under the filled. For example, when a magnesium with two valence electrons, oxygen bonds with six valence electrons, the oxygen atom gets two electrons from the magnesium to fill its octet. This forms a compound of MGO, magnesium oxide.

in the periodic table there are chemical elements with the sameValence electron configuration shown in the same group or vertical column. Members of each group tend to chemically react a similar way due to their common number of valence electrons. Elements with two valence electrons are found in Group 2 and include berylium, magnesium, calcium, strontium and barium. There may also be some transition metals such as iron and manganese.

bivalent ions are often important in chemistry. When the atom loses its two valence electrons, but uniformly connects, it becomes a positively charged ion or cation. Similarly, the atom, which obtains electrons from its neutral state, is considered an anion. For example, a sulfid, a bivalent anion, has a negative charge of two - has two more electrons than protons. Magnesium and calcium, which usually form bivalent cations, have a positive charge of two.

Calcium and magnesium cations often occur in hard water, water with a high mineral content. They also play a major role in biologicalprocesses. Calcium cations, for example, connect with proteins in cells and act as a signal messenger - in other words, stimulate events in the cell. They are also essential as a structural component of the cell walls of plants and in the activation of muscle contraction in animals.