structure and bonding

Question 1

covalent bonds

Answer 1

atoms share pairs of electrons, positive nuclei held by common attraction for share electrons, usually non-metal atoms

Question 2

polar covalent

Answer 2

medium difference in electronegativity values, and/or unsymmetrical molecular shape

Question 3

permanent dipole (polar partial charges)

Answer 3

atoms with higher electronegativity is delta -, atoms with lower electronegativity are delta +

Question 4

ionic bonds

Answer 4

electrostatic attraction between + and - ions

Question 5

ionic compounds

Answer 5

form lattice structures of oppositely charged ions

Question 6

bonding continuum

Answer 6

electronegativity
small/no difference - pure covalent
medium difference - polar covalent
large difference - ionic bonding

Question 7

ion electrons arrangement

Answer 7

atoms w/ lower electronegativity transfer electrons to atom w/ larger electronegativity value to form ions

Question 8

melting points

Answer 8

ionic - high
covalent networks - high
covalent molecular - low

Question 9

room temperature state

Answer 9

ionic - solid
covalent network - solid
covalent molecular - all gas/liquid compounds

Question 10

solubility

Answer 10

ionic compounds and polar covalent substance soluble in water as it is also polar.
non-polar substances more likely to be soluble in non-polar solvents.

Question 11

electrical conductivity and bonding

Answer 11

metallic - solid, liquid, not applicable in solution
covalent - none
ionic - liquid and in solution

Question 12

intermolecular forces

Answer 12

found between all atoms, molecule and compounds in every state

Question 13

van der waals

Answer 13

London Dispersion Forces (LDFs)
Permanent dipole- permanent dipole interactions (pd-pd)
hydrogen bonding (FON)

Question 14

London DIspersion Forces

Answer 14

between all atoms and molecules, weaker than other bonding types.
caused by temporary uneven electron distribution causing temporary dipoles which is then induced on neighbouring atoms.

Question 15

LDF strength

Answer 15

greater number of electrons = stronger LDF
larger molecules = stronger LDF

Question 16

permanent dipoles

Answer 16

found in polar molecules

Question 17

pd-pd interactions

Answer 17

permanent dipoles in each molecule attracted to each other
additional electrostatic forces of attraction (on top of london dispersion forces)

Question 18

symmetry and polarity

Answer 18

symmetrical - non-polar even if contains polar bonds
unsymmetrical - polar

Question 19

bonding strength

Answer 19

LDF < pd-pd < hydrogen bonding < ionic and covalent bonding

Question 20

hydrogen bonds

Answer 20

electrostatic forces of attraction found between molecules containing -
-OH, -NH, H-F

-OH - water, alcohols, carboxylic acids
-NH - ammonia, amines

Question 21

high melting and boiling points

Answer 21

stronger intermolecular forces are

Question 22

covalent compounds with hydrogen bonding

Answer 22

higher melting points, boiling points and viscosity than those with LDFs

Question 23

polar molecules -> non polar

Answer 23

stronger intermolecular forces when comparing molecules with similar electron numbers

Question 24

viscosity

Answer 24

hydrogen bonding - thicker
pd-pd - medium
LDF - thinner

Question 25

ice density

Answer 25

less than water due to hydrogen bonding expanding structure of ice compared to liquid water, unlike most substances its solid floats in its liquid