elektronegatiivsem

Elektronegatiivsem is a term used in chemistry to describe an atom's tendency to attract a shared pair of electrons towards itself in a covalent bond. It is a relative property, meaning that the electronegativity of an atom is measured in comparison to other atoms. The concept of electronegativity was first quantified by Linus Pauling in 1935, and his scale remains the most widely used.

On the Pauling scale, fluorine is the most electronegative element, assigned a value of 3.98. Conversely, francium is the least electronegative element, with a value of 0.7. Generally, electronegativity increases across a period from left to right in the periodic table and decreases down a group from top to bottom. This trend is influenced by factors such as atomic radius and nuclear charge.

The difference in electronegativity between two bonded atoms determines the type of chemical bond that forms. If the difference is very small, the bond is considered nonpolar covalent, meaning electrons are shared almost equally. A moderate difference results in a polar covalent bond, where electrons are shared unequally, creating partial positive and negative charges on the atoms. A large difference in electronegativity typically leads to the formation of an ionic bond, where one atom effectively "takes" electrons from the other, forming distinct ions. Understanding electronegativity is crucial for predicting molecular polarity, reactivity, and the physical properties of chemical compounds.