Chemistry Ch.3 - Understanding Chemical Compounds

Bonding Capacity

The maximum number of single covalent bonds an atom can form.

Valance Shell

The outermost/highest energy level

Valance Electrons

Electrons found in the valance shell

Bonding Electrons

A single unpaired electron that can be shared (COVALENT) or transferred (IONIC) to another atom

Lone Pair

Two valence electrons of an atom paired together

Octet Rule

States tce maximum number of electrons that can occupy the valence shell.

Chemical Bond

A force that holds 2 atoms together and makes them more stable

Forming a Bond

More Stable and Exothermic (More energy out then in)

Breaking a Bond

Less Stable and Endothermic (More energy in then out)

Electronegativity

Describes the relative ability of an atom to attract a pair of bonding electrons in its valence shell

(Measures an atom’s attraction for electrons it shares and determines type of bond)

Covalent / Nonpolar Bond

Equal sharing of electrons (Electronegativity >0.4)

Polar Covalent

Unequal sharing of electrons (Electronegativity 0.5 - 1.7)

Ionic

Electron Transfer (Electronegativity <1.7)

Ionic Bond

Loss of gain of electrons

• Cations = +

• Anions = -

Ionic Bond Charactersitics

• Crystalline at room temp

• Higher melting and boiling point

• Conducts electrical current in molten or solution state

• Extreme Polar bonds

Covalent Bond

Shares electrons to fill valence shell

• Between Nonmetals

Covalent Bond Characteristics

• Definite and predictable shapes

• Very Strong

• Low melting and boiling point

Metallic Bonding

Occurs in metals that consist of positive ions surrounded by mobile electrons

Metallic Bond Characteristics

• Good conductor of heat/electricity

• Great strength

• Malleable and Ductile

• Luster (Shiny)

Coordinate Covalent Bonds

One atom donates both electrons that are shared

Single Bond

Sharing 1 electron pair between 2 atoms

Double Bond

Sharing 2 electron pairs between 2 atoms

Triple Bond

Sharing 3 electron pairs between 2 atoms

Empirical Formula

Shows the simplest/lowest ratio of atoms in a compound

Molecular Formula

Shows the actual number of atoms that covalently bonded to make up a molecule. It often shows bonding order.

Lewis Formula

Shows electron sharing in covalent bonds that form stable valence octets in molecules and ions.

Structural Formula

Shows the way atoms are bonded through lines drawn between atoms.

Stereochemical Formula

Represents the 3d shape of molecules

Valence Shell Electron Pair Repulsion (VSEPR

Shows the geometry of a molecule

• Lone pairs and bonding pairs repe eachother since they have the same charge

Linear Shape

• 2 Bonded atoms to central atom and 0 Lone pairs (CO2)

• 2 Atom bonded together (CO)

Bent/Angular Shape

• 2 atoms bonded to central atom with 1 Lone pair (SO2)

• 2 atoms boned to central atom with 2 Lone pairs (H2O)

Trigonal Planar Shape

• 3 atoms bonded to central atoms and 0 Lone pairs (BCl3)

Trigonal Pyramidal Shape

• 3 atoms bonded to central atom with 1 Lone pair (NH3)

Tetrahedral Shape

• 4 atoms bonded to central atom with 0 Lone pairs