Chemical Bonds and Compounds

Ionic compounds form when positive cations combine with negative anions through electron transfer. When metals give electrons to non-metals, both atoms achieve complete valence shells. The resulting compound is neutral, with positive and negative charges balancing perfectly. These compounds are often called "salts" and don't use prefixes in their naming.

Covalent compounds form between non-metals through electron sharing rather than transfer. Atoms share unpaired electrons to complete their valence shells, forming molecules rather than charged ions. For example, fluorine atoms (F:F:) share electrons to create a covalent bond, with each atom achieving a complete "octet" (8 valence electrons). Hydrogen often forms a "duet" (2 valence electrons) as in H:F:.

Quick Tip: Remember the key difference - ionic bonds involve electron transfer (complete movement of electrons), while covalent bonds involve electron sharing (electrons belong to both atoms).

Molecules can form various shapes depending on how atoms bond. Common molecular shapes include linear, bent, pyramid, and tetrahedral arrangements. Bonds between atoms can be single, double, or triple, affecting both the molecule's shape and properties.

When naming covalent compounds, we use prefixes to indicate how many atoms are present $mono=1, di=2, tri=3, etc.$. The central atom is named first, followed by the non-metal with an "-ide" ending. The first non-metal only gets a prefix if it has a subscript greater than one.

Bond polarity depends on electronegativity differences. When atoms have similar electronegativity $like H-H$, electrons are shared equally in a non-polar bond. When electronegativities differ by 0.4 or more $like H-F$, electrons are pulled toward the more electronegative atom, creating a polar bond with partially positive and negative regions.