Unit 2: Molecular and ionic compound structure and properties

Covalent bonds are formed between

two nonmetals sharing electrons

Ionic bonds are formed when a metal

transfers electrons to a nonmetal and the opposite charges attract

The greater the electronegativity difference between 2 atoms

the more polar the bond becomes

Combustion reactions make..

CO2 and H2O

Carbon makes a total of

4 bonds in a compound

Bond angle: 4 domains = ?

109.5 degrees

Bond angle: 3 domains = ?

120 degrees

Bond angle: 2 domains = ?

180 degrees

Hybrid orbitals: 4 domains = ?

sp^3

Hybrid orbitals: 3 domains = ?

sp^2

Hybrid orbitals: 2 domains = ?

sp

Asymmetrical molecules =

dipoles DO NOT cancel = polar molecule

symmetrical dipoles =

nonpolar molecule

Single bond = ?

sigma

Double bond = ?

sigma + pi bond

Triple bond = ?

sigma + 2 pi bonds

Lattice energy is the energy to

break an ionic bond in a compound. (Coulomb's Law)

Lattice energy increase as

the ion's charge increases. (Coulomb's Law)

Lattice energy decreases as the

radii of the ions increase. (Coulomb's Law)

Formal charge involves comparing the # of valence electrons an atom has to

the # of electrons around it in the Lewis structure.

Formal charge = ?

valence electrons - lone pair electrons - 1/2 bonding electrons

Obey the octet rule first when drawing the Lewis Dot structure

then use formal charge if necessary.

Extra electrons can go on the larger central atom, and

if you have too few electrons, start making some double or triple bonds.

Metallic bonds are between metals, and

they ALWAYS conduct electricity, and their hardness varies.

Interstitial alloys are made

when a smaller atom fits into the gaps between the larger atoms of a metallic crystal.

Substitutional alloys are made

when the radii of the metals are similar in size and are substituted into the crystal latiice.