Chemical Bonds Study Guide

Compounds are either:

o A molecule with covalent bond

o Formula unit with ionic bond

* Molecules: formed by covalent bonds

* Lattice energy is the energy released in the formation of an ionic compound.

DEFINITION: The formation of an IONIC BOND is the result of the transfer of one or more electrons from a metal onto a non-metal.

Characteristics of both bonds:

* Occur between 2 atoms

* Composed of 2 electrons

* Have both ionic and covalent characteristics

* Together = 100%

* Both bonds are measured on an electronegativity scale

* Both contain a nonmetal

* Chemical bonds

* Are determined by using the “magic number” (1.67)

* Have bond angle and bond axis

Characteristics of metallic bonds:

* In metals (d-block electrons only..because of shape and prop.)

* They’re delocalized (no electron ‘belongs’ to any one atom)

* Known as the “sea of elements” because they’re floating around

* Atomic radius determines how close atoms can get

Hydrogen bonding:

* Dipole-Dipole attraction

* Occurs between H atoms (positive charge) and highly electronegative

atoms (negative charge) such as O, N, F

* δ = lowercase delta (+/-)

* hydrogen reacts with a lone pair

* Transient bond (temporary)

* H has a high boiling point

* Ice has crystalline structure

* Water molecule is bent: 107.5° angle

* Adhesion: between molecules and surface

* Cohesion: between molecule and molecule

* Intermolecular: forces between molecules which hold two or more of them together. (ex. between hydrogen and

oxygen, sulfur, nitrogen or fluorine)

* Intramolecular: forces happen inside the molecule and are the forces holding the atom together which form the molecule. (ex. Ionic and covalent bonds)

* Dipole-Dipole forces: Polar covalent molecules are sometimes described as "dipoles", meaning that the molecule has two "poles". One end (pole) of the molecule has a partial positive charge while the other end has a partial negative charge.

* Potable: water that is drinkable

* Choler: bacterial infection causes dysentery

Shapes:

* 2 bonding, 1 lone pair: Bent

* 3 bonding, 0 lone pairs: Trigonal Planar

* 2 bonding, 0 lone pairs: Linear

* 4 bonding, 0 lone pair: Tetrahedral

* 4 bonding, 2 lone pairs: Square Planar

* 5 bonding, 0 lone pairs: Trigonal Bipyramidal

* 3 bonding, 1 lone pair: Trigonal Pyramidal

* 6 bonding, 0 lone pairs: Octahedral

* 5 bonding, 1 lone pair: Square Pyramidal

* Electrons determine the shape (electron configuration) because the electrons

pull away from each other

* A carbon is in the middle of a tetrahedral

* # of atoms:

* 2-linear

* 3-linear/bent

* 4-Trigonal planar