Lesson 1, Topic 1
In Progress

02-Chemical Bonding

March 28, 2021

Chemical bonds form to make atoms more stable. Atoms react with one another in ways that make their outermost energy level fill to capacity. Atoms may share electrons or donate or borrow them to become stable.

Ions form when an atom gains or loses electrons in its outer energy level to become more stable. A positive ion is one that has lost electrons, which is indicated by the superscript positive sign (or signs), as in sodium, expressed as Na with one superscript plus sign, or calcium, expressed as Ca with two superscript plus signs. A negative ion is one that has gained electrons, indicated by the superscript negative sign (or signs), as in chloride, expressed as Cl with one superscript minus sign. Ionic bonds form when positive and negative (that is, oppositely charged) ions attract each other. An electrolyte is a substance that dissociates or breaks apart in water to form individual ions.

Covalent bonds form when atoms share their electrons rather than donating or accepting them. The driving force behind sharing electrons is that of striving to fill up the outer energy level, and thus become stable. Covalent bonds do not ordinarily dissociate easily in water. All of the major organic compounds found in the body make use of covalent bonds.

When hydrogen bonding occurs, the formation is not a new molecule , but rather a weakly bound assembly of neighboring molecules. Hydrogen bonds are present in water, DNA, and proteins.