ib chem structure 2 test pt 2

dipole moment

separation of charge between 2 identical bonded atoms, greater difference = greater dipole

molecule polarity

nonpolar covalent bonds → nonpolar molecule

polar covalent bonds → nonpolar (symmetrical) and polar (nonsymmetrical) molecules

london dispersion forces

temporary and instant dipoles that induce a temporary dipole in surrounding molecules created by random movements of electrons inside the molecule

weakest, nonpolar → polar

dipole

a pair of equal and oppositely charged or magnetized poles separated by a distance

dipole dipole

permanent dipoles attracted to permanent dipoles, positive end of H2O attracted to the negative end of another

exhibits LDFs, polar → polar

hydrogen bonds

specific dipole dipole, polar H molecules attracted to F, O, N

exhibits LDFs, polar → polar

dipole induced

permanent dipole pulls/is attracted to an ionic compound, then pulls it apart by water surrounding it, the negative end surrounds the positive end

high IMFs = — volatility

low in covalent networks and high in molecules

superconductor properties

high MP/BP = low radius

high charges in metal

high amount of density and electrons

low temp = low electrical resistance

lattice energy

tells how strong an ionic bond is

more energy levels = further distance = weaker attraction

lattice structure

continuous 3D structure

when you dont have enough valence electrons in a lewis structure

add double and triple bonds

when you have too many valence electrons in a lewis structure

add nonbonding pairs

exceptions to the octet rule

Helium: 2

Hydrogen: 2

Carbon: 4

Beryllium: 4

Boron: 6

Aluminum: 6

Sulfur: 8 or 12

Xenon: 8 or 12

formal charge

formal charge = valence electrons - assigned electrons

for negative charges, extra electrons are assigned to the most electronegative element

linear (2ED)

2ED

AB2

180

CO2

Symmetrical

Trigonal planar

3ED

AB3

120

BH3

Symmetrical

Bent (3ED)

3ED

AB2E

120

SO2

Tetrahedral

4ED

AB4

CH4

109

Symmetrical

Trigonal Pyramidal

4ED

AB3E

104

NH3

Bent (4ED)

4ED

AB2E2

109

H2O

Trigonal bipyramidal

5ED

AB5

180, 120, 90

PF5

Symmetrical

Seesaw

5ED

AB4E

180, 120, 90

SF4

T-shaped

5ED

AB3E2

180, 90

ClF3

Linear (5ED)

5ED

AB2E3

180

XeCl2

Symmetrical

Octahedral

6ED

AB6

180, 90

SF6

Symmetrical

Square pyramidal

6ED

AB5E

90

BrF5

Square planar

6ED

AB5E2

90

XeF4

Symmetrical