Unit 8 - Chemical Bonding

Question 0

Open Shell

Closed Shell

Answer 0

One that contains less than the max # of e-s

One that contains the max # of e-s

Question 1

Electrostatic Force

Answer 1

Force of attraction or repulsion between charged particles
Greater the charges, greater the attraction/repulsion
Greater the distance between particles, weaker the force

Question 2

Atomic Radii

Answer 2

Determined by x-Ray diffraction
Decrease as you move down the period
Increase down the family

Question 3

Valence E-s

Answer 3

Electrons found in open shells

E-s available for and involved in bonding

Question 4

Valence

Answer 4

The combining power of an element

Question 5

Ionization Energy

Answer 5

The amount of energy needed to remove a valence electron from an atom in the gas state
Increases as you go up and to the right

Question 6

Electronegativity

Answer 6

A measure of the ability to steal e-s
Very attractive to valence e-s of neighbouring atom
Strongly attract their own valence e-s

Answer 7

Tells you what kind if bond to expect between two atoms
> or = to 1.7 ionic compound
< covalent compound

Question 8

Ionic Bond

Answer 8

Formed by the electrostatic force of attraction between a cation and anion
Usually involves metal and non-metal
Metal atom loses e-, non-metal gains one to complete their valence shells
Held together by their attraction of opposite charges

Question 9

Lewis Structures

Answer 9

Show e-s in the valence shell of an atom, ion, or molecule

Question 10

Structure of Ionic Compounds

Answer 10

Crystal Lattices held together by ionic bonds
*groups 14/15 partially predictable
C, Si, Ge, don't usually form ions
Sn, Pb, form 2+ or 4+
Bi, forms 3+ or 5+

Question 11

Covalent Bond

Answer 11

Formed when two atoms complete their octets by sharing one or more pairs of e-s
Usually involves 2 non-metals
Both nuclei get to be attracted to more e-s, so covalent bonds V strong

Question 12

Single Covalent Bonds

Answer 12

Formed when two atoms share a single pair of e-s

Ex. homogenous diatomic molecules (HOFBrINCl)

Question 13

Coordinate Covalent Bonds

Answer 13

Atoms that have a non-bonding e- pair in their octet can share to allowance “electron deficient partner” to complete their octet/duet

Question 14

Exceptions to Octet Rule

Answer 14

Electron Deficient Molecules
Ones with fewer than 8 valence e-s

Expanded Valence
Central atoms from 3rd/4th periods can be surrounded by more than 8 e-s
P: (up to 10) S: (up to 12)

Question 15

Bond Energy

Answer 15

The energy needed to separate two bonded atoms

KJ/mol

Question 16

Single Vs Double Vs Triple

Answer 16

Single - longest bond length
Single - weakest bond strength
Single - least reactive

Question 17

VSEPR Theory

Answer 17

Valence shell electron pair repulsion theory
Lone pairs = valence e-s on each central atom that are not involved in bonding
Bonding pairs = “” “” that are involved in bonding
All bonding/non-bonding pairs called structural pairs

Question 18

Structural Pair Geometry

Answer 18

The arrangement of structural pairs around a central atom

Question 19

Molecular Shape

Answer 19

The arrangement of the atoms bonded around a central atom

Question 20

Covalent Crystals

Answer 20

Form when a whole network of atoms are covalently bonded together

Bonded together they for, crystal lattices or networks

Ex. Diamond, silicon carbide, boron nitride

Question 21

Allotrope

Answer 21

A structural variation of an element within the same state
Most well-known:
Phosphorus (white,red,etc)
Oxygen (02/03) and carbon (coal, diamond, graphite, and the fullerenes)

Question 22

Many Covalent bonds have low melting points

Answer 22

It’s because there are other types of bonding responsible for the phases of these substances
So for H2O, when ice melts it’s the weaker forces of attraction that break, not the covalent bonds
Ex.
CH4 -183 C
O2 -219 C
F2 -220 C

Question 23

Change =

Partial =

Answer 23

Triangle

Weird bottom looped S

Question 24

Polar Covalent

Answer 24

One with one or more electron pairs shared unequally
Occurs when 0.2 < ^X < 1.7
The electron density is enriched around the more electronegative element and is deficient around the less electronegative element

Question 25

Polar Molecule

Non-Polar Molecule

Answer 25

One where there is an imbalance in the total sharing of electrons within the molecule. Require polar covalent bonds and must be asymmetric

One where the total sharing of electrons is balanced. Requires equal and symmetric polar covalent bonds

Question 26

The more polar a molecule is, the more attractive it is to other polar molecules

Answer 26

The melting and boiling temperatures of all covalent compounds depend on the forces of attraction between molecules

Question 27

Intramolecular Forces

Answer 27

Forces that act within molecules

Question 28

Intermolecular Forces

Two types are:

Answer 28

Attractive forces between molecules

Dipole-dipole Forces
London Forces

Question 29

Dipole-Dipole Forces

Answer 29

Forces of attraction between polar molecules
Dominant intermolecular force between polar molecules
Strongest is the hydrogen bond
Only capable between models containing_____,___,____
Have strongest polarity because they create the biggest dipoles and have highest electronegativity

Question 30

London Forces

Answer 30

Are weak attractive forces between non-polar molecules weakest of all inter molecule forces
Strength grows as # e-s

Question 31

Conductivity

Answer 31

Metal atoms held together in condensed states by metallic bonding
Results from the simultaneous attraction of multiple nuclei for the same e-s
Since metals have low electronegativity, the e-s can easily move from one atom to the next; why they’re such good electrical conductors
“Mobile sea of e-s” sloshing around inside

Question 32

Melting Point/Reactivity

Answer 32

The greater the atomic radius, e weaker the attractive force between nucleus of a given atom and the valence e-s of neighbouring atoms
Bigger metal atoms tend to have weaker metallic bonds, lower melting points, and are more reactive because their valence e-s have lower ionization energy and are more easily removed

Question 33

Alkali Metals

Answer 33

Silver coloured, soft, low density, highly reactive, not found in nature, react vigorously with water
MP lowers going down family
BP lowers going down family

Question 34

Alkaline Earth Metals

Answer 34

Silver coloured, soft metals, react with water to form strong alkaline hydroxides
MP/BP decreases going down family, because the metallic bonds weaken
Metals react by losing e-s, so reactivity goes up when going down the family
Atomic # increases, more valence shells added and valence e-s further from nucleus, ionization down

Question 35

Halogens

Answer 35

Fluorine- pale yellow green gas, highest reactivity
Chlorine- pale green yellow colour
Bromine- dark red brow. Liquid
Iodine- violet black solid, slightly metallic lustre
MP/BP increases going down
All diatomic molecules, London forces bonding ‘em
Are NON METALS so they want to GAIN e-s to complete their octets

Question 36

Noble Gases

Answer 36

Colourless and odourless at room temperature
Generally do not react with other elements
London forces responsible for the condensed state of noble gases, since they lack a permanent dipole
MP/BP increases going down family