classic covalent bond

Formulas in which atomic symbols represent nuclei and inner-shell electrons, dot pair or dashes between two atomic symbols represent electron pairs in covalent bonds, and dots adjacent to only one atomic symbol represent unshared electrons.

Structural formulas identify the location of chemical bonds between the atoms of a molecule. A structural formula consists of symbols for the atoms connected by short lines that represent chemical bonds—one, two, or three lines standing for single, double, or triple bonds, respectively. For example,…

Covalent bonds where electrons are not shared equally between two atoms are called polar covalent bond. As shown above, the electrons in a covalent bond between two different atoms (H and Cl in this case) are not equally shared by the atoms. This is due to the electronegativity difference between the two atoms.

polar covalent bonds

covalent

Ionic bonds form when one atom gives up one or more electrons to another atom. a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.

Two or more atoms held together by covalent bonds in a specified arrangement is called a molecule. The diagram below illustrates the covalent bond that forms between two hydrogen atoms to form a molecule of hydrogen.

compounds

At the center of an atom is a nucleus made up of two types of particles called protons and neutrons. Protons have a positive electrical charge. The number of protons in the nucleus determines what element the atom is. Neutrons are about the size of protons but have no charge.