1.2.2 BONDING & STRUCTURE

?
What is ionic bonding?
electrostatic bonding between oppositely charged ions
1 of 64
How would you illustrate ionic bonding?
outermost shell illustrated (even if now empty) with square brackets with charge on outsode
2 of 64
between which elements does ionic bonding take place?
1-2 metals react with 5-7 non-metals
3 of 64
state the charge and formulae of nitrate
NO3-
4 of 64
state the charge and formulae of sulphate
SO4^-2
5 of 64
state the charge and formulae of ammonium
NO4^+
6 of 64
state the charge and formulae of carbonate
CO3^-2
7 of 64
What is a covalent bond?
shared pair of electrons
8 of 64
What is dative covalent bonding?
both electrons in the bond are supplied by the same atom
9 of 64
How is dative covalent bonding represented?
-> arrow towards atom that is accepting
10 of 64
Give an example of a molecule/ion with a dative bond
NH4+ // H3O+ // NH3BF3
11 of 64
how is covalent bonding illustrated?
two outer shells overlapping 'dot and cross'
12 of 64
How is the shape of a simple molecule determined?
by the repulsion between electron pairs surrounding the central atom
13 of 64
Describe the characteristics of lone pairs of electrons
they repel more than bonded pairs, decreases bonding angle by 2.5
14 of 64
What is the shape and bond angle of a molecule with 2 bonding regions
linear - 180
15 of 64
What is the shape and bond angle of Carbon Dioxide?
linear - 180
16 of 64
What elements covalently bond?
non-metals
17 of 64
What is the shape and bond angle of a molecule with 3 bonding regions?
trigonal planar - 120 (all on same plane)
18 of 64
What is the shape and bond angle of a molecule with 3 bonding regions and a lone pair?
v-shaped - 117.5
19 of 64
what is the shape and bond angle of a molecule with 4 bonding regions?
tetrahedral - 109.5
20 of 64
Describe the planar structure of tetrahedral molecules
two on plane, one inwards and one outwards
21 of 64
what is the shape and bond angle of a molecule with 4 bonding regions and a lone pair?
trigonal pyramidal - 107 - one in each plane
22 of 64
What is the shape and bond angle of a molecule with 4 bonding regions and 2 lone pairs?
bent (non-linear) - 104.5
23 of 64
what is the shape and bond angle of a molecule with 6 bonding regions
octahedral - 90
24 of 64
How are simple molecules bonded?
covalently
25 of 64
Describe the planar structure of an octahedral molecule
two bonds each in same plane - each opposite to each other
26 of 64
How do you explain the shape of a molecule?
1. state number of pairs of electrons 2. state n of lone pairs 3. if all repel equally or not 4. shape and angle
27 of 64
What is electronegativity?
ability of an atom to attract the bonding electrons in a covalent bond
28 of 64
What factors affect electronegativity?
increases across a period as proton n and atom radius decrease // decreases down a group as atoms get larger there is more shielding and distance increases
29 of 64
when will a compound be purely covalent?
compound contains elements of similar electronegativities
30 of 64
how does a permanent dipole form?
when covalently bonded atoms have different electronegativites, resulting on a polar-bond
31 of 64
what happens when a covalent bond is polar?
bond has unequal distribution of electrons which results in a charge seperation
32 of 64
what is bond polarisation?
when a covalent bond becomes slightly ionic in charge because it has a dipole moment
33 of 64
How can you find if a bond has a dipole?
difference in EN // 0.5-1.6 = dipoles // 2.0 < = dipoles // IF EN is 1.6-2.0 between metals then dipole
34 of 64
What are Van der Waals?
very weak attractive forces between induced dipoles in neighbouring molecules
35 of 64
How do Van der Waals occur?
constant imbalance of electrons in molecules results in instantaneous dipoles which induces dipoles in neighbouring molecules
36 of 64
What are the characteristics of Van der Waals?
they are between all molecules and atoms // force of VdW increase the more electrons present// present in noble gases
37 of 64
What are permanent dipole-dipole interactions?
weak attractive forces between permanent dipoles in neighbouring polar molecules
38 of 64
How do permanent dipole-dipole interactions occur?
polar molecules have permanent dipoles // dipole in one molecule attracts dipole in another
39 of 64
What is a hydrogen bond?
strong dipole-dipole attraction between an electron deficient hydrogen atom and a lone pair of electrons on a highly EN atom on a different molecule
40 of 64
How do hydrogen bonds occur?
When polarised covalent bonds cause H atoms to form bonds with lone pairs of electrons on FON atoms of other molecules
41 of 64
How does structure and bonding affect the noble gases?
going down the group electron n increases // VdW increase // BP increases// VdW are the only forces // without VdW would not be able to liquify
42 of 64
what is an intermolecular force?
an attractive force between neighbouring molecules
43 of 64
State the special properties of H2O
ice is less dense than water // relatively high MP and BP // solubility
44 of 64
How is ice less dense than water?
ice has open lattice structure with H bonds holding molecules apart (when melts these bonds collapse)
45 of 64
Why does water have a relatively high melting and boiling point?
H bonds hav veto be overcome
46 of 64
Explain the solubility of water
can dissolve ionic substances as dipoles (H and O) attracts oppositely charged ions - breaking apart giant ionic lattice structures
47 of 64
What is metallic bonding?
electrostatic force of attraction between positive metal ions and delocalised electrons
48 of 64
What factors affect the strength of a metallic bond?
number of protons/ nuclear attraction - more protons stronger bond// number of delocalised electrons per atom// size of the atom - smaller=stronger
49 of 64
describe the structure of a giant ionic lattice
structure of an ionic compound made up of + and - ions held in place by strong electrostatic forces of attraction between oppositely charged ions
50 of 64
give an example of a giant ionic lattice
crystalline substances (salts) ie NaCl
51 of 64
What are the characteristics of giant iconic lattices?
solids at RTP // large amount if energy required to break bonds// non conductors as no free ions// can conduct as liquids
52 of 64
What is a giant covalent lattice?
three-dimensional structure of atoms bonded together by strong covalent bonds
53 of 64
give some examples of giant covalent lattices
diamond // silicone dioxide// graphite
54 of 64
what are the characteristics of giant covalent lattices?
very high MP/BP, strong bonds// non conductors as no free electrons// insoluble
55 of 64
what is the structure of diamonds?
tetrahedral structure, macromolecular structure of covalent bonds// 4 covalent bonds per atom
56 of 64
describe the characteristics of diamonds
poor conductivity// very strong and hard// shape allows forces to spread throughout lattice
57 of 64
What is the structure of graphite?
hexagonal planar structure in layers of covalent bonds// 4th electron per atom is delocalised - delocalised between layers
58 of 64
Describe the characteristics of graphite
good conductor as electrons free to move between layers// high MPBP // soft, sliding layers
59 of 64
What is a simple molecular lattice?
a three dimensional structure of molecules, bonded together by weak intermolecular forces
60 of 64
describe a simple molecular lattice
individual molecules with strong covalent bonds// all types of intermolecular forces
61 of 64
describe the characteristics of simple molecular lattices
low MPBP due to weak intermolecular forces // low solubility // non conductive
62 of 64
What is a giant metallic lattice?
three-dimensional structure of positive ions and delocalised electrons, bonded together by strong metallic bonds
63 of 64
Describe the characteristics of giant metallic lattices
high MPBP due to electrostatic forces// good conductors due to electrons// ductile and malleable planes of + can slide over each other
64 of 64

Other cards in this set

Card 2

Front

How would you illustrate ionic bonding?

Back

outermost shell illustrated (even if now empty) with square brackets with charge on outsode

Card 3

Front

between which elements does ionic bonding take place?

Back

Preview of the front of card 3

Card 4

Front

state the charge and formulae of nitrate

Back

Preview of the front of card 4

Card 5

Front

state the charge and formulae of sulphate

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Bonding & shapes resources »