What is a lonely couple?

The

lone couple refers to a few electrons in the valence shell atom that is not bound to another atom or molecule. Since only those electrons in the valence or external, shells of the atom participating in gluing are studied in chemistry by lonely pairs to take into account different molecules with the same number of bonds. Because electrons repel each other, molecules that have central atoms with a lonely pair will be shaped differently than those that do not.

electrons orbit the orbiting atom core in various shells. Each shell can hold a certain number of atoms and electrons always orbit in pairs, spinning in the opposite directions. Electrons in the outer shell of the atom, called a valence shell, can be shared with other atoms to form links and form molecules. In some molecules, all electrons of valence shells in the central atom are associated with a different atom, but in others they are only connected. A pair of electrons in an atom that is not associated with anotherA lonely couple.

In chemistry, couples of loans are studied because they affect the way of shaping certain molecules, which in turn can affect how the molecules behave. Explained by the theory of the electron pair of valence shells (VSEPR), electrons are naturally repelled by each other, corresponding to the shapes of different molecules. For example, the Berylium chloride (Brcl _{2 ) consists of a berylia atom bound to two chlorine atoms. Each chlorine atom is connected to the berylia atom with a pair of berylli electrons through a covalent binding. Since there are no undeveloped electrons in the valence shell, the furthest apart, the electrons that hold the chlorine atoms, can move 180 ° apart, creating a linear molecule.}

However, the tin chloride (SNCL 2 ) has an electron loan. Like the Bernyllium chloride, the tin chloride has two chlorine atoms connected by tin using an electron pairat. Unlike Berylia chloride, the tin chloride has another non -discarded pair of electrons, a lonely couple, also in the valence shell. This results in a tin chloride molecule with a bent shape, because all three pairs of electrons try to move the maximum distance apart.

The resulting angle between chloride atoms should then be 120 °. However, scientific research has found that it is actually 95 °. This mismatch is the result of the orbit of a pair of loans. The orbital pair of the loan is larger than the orbital couple, leading to the angle between smaller atoms.