1
Q
What are the shells of an atom identified by, and what symbol represents this?
A
Their principal quantum number (n)
2
Q
What happens as you move along the shells further away from the nucleus?
(2)
A
Shells become larger
Greater energy is stored by the electrons in the shell
3
Q
How many electrons can fill the first shell?
A
2
4
Q
How many electrons can fill the second shell?
A
8
5
Q
How many electrons can fill the third shell?
A
18
6
Q
How many electrons can fill the fourth shell?
A
32
7
Q
What is an atomic orbital?
A
a region around the nucleus that can hold up to two electrons with opposite spins. It forms part of the subshell which forms part of the shell
8
Q
what is a quantum number?
A
a set of numbers used to define the state of an electron
9
Q
How many electrons can be in an atomic orbital?
A
2
10
Q
What is important about the electrons in an atomic orbital?
A
they have opposite spin
11
Q
What are the 4 types of orbital?
A
s orbital
p orbital
d orbital
f orbital
12
Q
What is the shape of s orbitals?
A
spherical
13
Q
which shells contain s orbitals?
A
All of them
14
Q
how many s orbitals are there per shell?
Therefore how many electrons are held in the s orbital in each shell?
A
a) 1
b) 2
15
Q
What shape are p-orbitals?
A
3 dimensional dumbbell shape
16
Q
Which shells have p-orbitals?
A
from n=2 upwards
17
Q
a) how many p-orbitals are there in each shell?
b) how many electrons are there in p-orbitals in each shell?
A
a) 3
b) 6
18
Q
What is a subshell?
A
all the orbitals of one type in a shell
19
Q
Which shells have d-orbitals?
A
From n=3 upwards
20
Q
How many d-orbitals are there in a subshell?
A
5
21
Q
How many electrons can be held in d-orbitals in a shell?
A
10
22
Q
How many electrons can be held in f-orbitals in a shell?
A
14
23
Q
How many f-orbitals are there in a subshell?
A
7
24
Q
Which shells have f-orbitals?
A
n=4 upwards
25
How do we represent spin?
With an arrow, facing up or down
26
Practice box diagrams!
27
practice electronic configurations!
can't write them on electronic flashcard
28
In what order are subshells filled?
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
29
What are the two exceptions to the way shells are filled?
copper and chromium
30
How is copper an exception?
Why is it filled in this way?
3d is completely filled whilst 4s only has one
This is because it is energetically favourable, making it more stable
31
why is chromium an exception?
each d orbital in 3d is filled with one electron whilst there is only one electron in 4s
32
what are the three rules/principles that control how electrons are added to orbitals?
Aufbau principle
Pauli's exclusion principle
Hund's rule
33
What is Aufbau principle?
Electrons fill atomic orbitals starting with the lowest available energy levels before occupying higher energy levels
34
What is Pauli's exclusion principal?
No two electrons in one atom can have the same 4 quantum numbers (so electrons in the same orbital have opposite spin)
35
What is Hund's rule?
Orbitals in a given sublevel are half filled before they are completely filled
36
Where are electrons taken out of or given to to form ions in s and p block elements?
The outermost subshell
37
How are ions of d-block elements formed and why?
By losing electrons from the s orbital of the outer shell
(Eg. with 4s and 3d)
4s has lower energy so is filled first, however, since it is so close in energy to the 3d subshell, it empties before 3d shell
38
What is ionic bonding?
the electrostatic attraction between positive and negative ions
39
Explain the structure of solid giant ionic lattices
Each ion in the lattice is electrostatically attracted to the oppositely charged ions, so they surround themselves with them, forming a lattice which stretches in all directions with a regular, repeating pattern
40
State 3 key behaviours of ionic compounds
high melting and boiling points
electrical conductivity
solubility
41
Why do ionic compounds have high melting and boiling points?
large amount of energy needed to break strong electrostatic forces between oppositely charged ions
42
When and why do ionic compounds have electrical conductivity?
they conduct electricity when molten or in aqueous solution because the ions are free to move
43
The greater the charge the ___ the electrostatic attraction
greater
44
Discuss the solubility of ionic compounds
they are soluble in polar solvents
Their dissolution depends on:
-the ionic lattice must be broken down
-water molecules must attract and surround the
ions
45
If charges of the ionic compound increase, solubility often ___ because___
decreases
the water molecules cannot overcome the forces of attraction
46
Define a covalent bond
the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
47
Discuss the amount of bonds atoms can make
Atoms don't always form shells of eight electrons
From n=3 onwards, can have higher numbers in outer shell
This means same two elements can make multiple compounds
max no. of pairs = no. of electrons in outer shell
48
From which shell can atoms make more than eight bonds on their outer shell?
n=3
49
What is a dative covalent bond?
a covalent bond where both electrons in the electron pair come from the same atom
50
What is average bond enthalpy a measure of?
covalent bond strength
51
the ___ the value if average bond enthalpy, the stronger the covalent bond
larger
52
as you go from a single bond to a triple bond, bond enthalpy __
as you go from small atoms bonding to big atoms bonding, bond enthalpy __
as you go from a symmetrical bond to an unsymmetrical bond, bond enthalpy __
increases
decreases
decreases
53
Define polar molecule
a molecule where one end of the molecule is slightly -ve and the other is slightly +ve due to an unequal distribution of electrons
54
When does a molecule have a dipole moment?
when there is an unequal distribution of electrons across the entire molecule
55
as you go across the period (from _ to _) atomic radius _ because _
left to right
decreases
number of protons increases, meaning that the outermost electrons are held more tightly because the positive charge of the nucleus is greater
56
as you go down the group (from _ to _) atomic radius _ because _
up to down
increases
number of shells increases
57
what is electronegativity?
the measure of the tendency of an atom to attract a bonding pair of electrons (eg. electrons closer to oxygen in water because electronegativity is higher) in a covalent bond
58
What are the most and least electronegative elements?
most- fluorine
least- francium (don't need to remember)
59
Describe the intra and intermolecular forces of small covalent molecules
strong covalent bonds (intramolecular forces)
weak intermolecular forces
60
Discuss the solubility of simple molecular compounds
polar molecules are soluble in polar solvents
compounds with hydrogen bonding are soluble in water
molecules that are non polar are insoluble or only slightly soluble in water
61
give 4 giant covalent lattices
diamond
graphite
silicon dioxide
buckminsterfullerene
62
Why can't giant covalent lattices dissolve?
to dissolve, bonds must break and new ones between substance and water must form
new bonds are weaker than old, so this doesn't happen
63
discuss the conductivity of certain giant covalent lattices
diamond is an excellent thermal conductor (because atoms close together)
graphite is an excellent thermal and electrical conductor
64
Give the 7 shapes of molecules you need to know
linear
trigonal planar
tetrahedral
pyramidal
non linear/bent
trigonal bipyramidal
octahedral
65
How many electron pairs/groups of pairs does linear have
2
66
How many electron pairs/groups of pairs does trigonal planar have
3
67
How many electron pairs/groups of pairs does tetrahedral have
4
68
How many electron pairs/groups of pairs does pyramidal have
4
69
How many electron pairs/groups of pairs does non linear/bent have
4
70
How many electron pairs/groups of pairs does trigonal bipyramidal have
5
71
How many electron pairs/groups of pairs does octahedral have
6
72
how many bonding pairs/groups of bonding pairs does linear have?
2
73
how many bonding pairs/groups of bonding pairs does trigonal planar have?
3
74
how many bonding pairs/groups of bonding pairs does tetrahedral have?
4
75
how many bonding pairs/groups of bonding pairs does pyramidal have?
3
76
how many bonding pairs/groups of bonding pairs does non linear/bent have?
2
77
how many bonding pairs/groups of bonding pairs does trigonal bipyramidal have?
5
78
how many bonding pairs/groups of bonding pairs does octahedral have?
6
79
What shapes have zero lone pairs?
linear
trigonal planar
tetrahedral
trigonal bipyramidal
octahedral
80
How many lone pairs does pyramidal have?
1
81
How many lone pairs does non linear/bent have?
2
82
What shape is it?
2 bonded electron pairs
0 lone electron pairs
linear
83
What shape is it?
3 bonded electron pairs
0 lone electron pairs
trigonal planar
84
What shape is it?
4 bonded electron pairs
0 lone electron pairs
tetrahedral
85
What shape is it?
3 bonded electron pairs
1 lone electron pairs
pyramidal
86
What shape is it?
2 bonded electron pairs
2 lone electron pairs
non linear/ bent
87
What shape is it?
5 bonded electron pairs
0 lone electron pairs
trigonal bipyramidal
88
What shape is it?
6 bonded electron pairs
0 lone electron pairs
octahedral
89
What is the bond angle in linear?
180°
90
What is the bond angle in trigonal planar?
120°
91
What is the bond angle in tetrahedral?
109.5°
92
What is the bond angle in pyramidal?
107°
93
What is the bond angle in non linear/bent?
104.5°
94
What are the bond angles in trigonal bipyramidal?
90° between bonds on same plane
120° between behind and in front bonds
95
What are the bond angles in octahedral?
90°
96
Name the theory to do with the shape of molecules
Valence shell electron pair repulsion theory (VSEPR)
97
What causes molecules to form 3D shapes?
Electrons repel each other
The shape adopted is always the lowest energy where the electron pairs are as far away from each other as possible to minimise repulsion.
98
Order from least to most repulsion
> bond pair/bond pair
> lone pair/lone pair
> bond pair/lone pair
bond pair/bond pair
bond pair/lone pair
lone pair/lone pair
99
define intermolecular force
an attraction between molecules
100
what are the two main types of intermolecular force
* hydrogen bonds
* Van der Waals forces
101
Define hydrogen bond
a strong permanent dipole-dipole interaction between an electron deficient hydrogen from one molecule and a lone pair from a highly electronegative atom on a different molecule
102
how do we represent a hydrogen bond?
By a vertical dashed line
103
why does electronegativity increase along the period
because increase in number of protons so electrons attracted more
104
why does electronegativity decrease down the group
there is more electron shielding
105
When will a molecule be polar?
bonded atoms have a high difference in electronegativity and the molecule is asymmetrical
106
What does hydrogen bonding happen between?
Between an N, O, or F atom in a molecule and the H-atom of N-H, O-H, or F-H in another molecule
107
order intermolecular forces from strongest to weakest
1) hydrogen bonding
2) permanent dipole-dipole interactions
3) London forces
108
Give the two types of Van der Waals forces you need to know
permanent dipole-dipole
instantaneous dipole- instantaneous dipole (London forces)
109
How do we represent the bond between two instantaneous dipoles
dotted/horizontal dashed line
110
how do we get london forces?
At any point a nonpolar molecule can have an uneven distribution of electrons
This means that one side is partially positive and other partially negative
Electrons on another atom near the positive will move towards it and electrons on an atom near the negative will move away from it - this induces a dipole in this atom
111
The _ the number of _ , the _the dipole so the greater the London forces
greater
electrons
greater
112
Which substances can be polarised and form instantaneous dipoles?
ALL molecules
NO lattices, so no ionic or metallic
113
Why is ice less dense than water
when water freezes, its molecules form a lattice with a fixed, open hexagonal structure, due to the hydrogen bonds that form. This structure pushes the molecules farther apart than they are in liquid water, increasing the volume for the same mass and thereby decreasing the density
114
water has relatively ____ v_____ and __ s__ __
high viscosity and surface tension
115
Which two elements do we need to know have similar electronegativity?
carbon and hydrogen
116
why does water have a relatively high melting and boiling point?
It has hydrogen bonds
117
explain the solid structure of covalent molecules
the molecules are attracted together by weak intermolecular forces that hold them together into a simple molecular lattice.
118
Why are ionic compounds generally soluble in water?
water molecules are polar and surround the ions in solution
119
Suggest why solid ammonia has a lower melting point than ice
Ammonia has weaker hydrogen bonds than ice/water because N has one lone pair whilst O has 2
120
Do you measure from top or bottom of the meniscus?
Bottom
121
Are hydroxides mostly soluble or insoluble?
insoluble
Chemistry
flashcards
Decks in class (10)
# Cards
-
Module 2.1 -atoms, compounds,molecules and equations98
-
Module 2.2 electronic structure121
-
Module 3.1- the periodic table48
-
Module 3.2- physical chemistry62
-
mod 3 to practice1
-
Module 4.1 set 1 basic concepts of organic chemistry131
-
Module 4.1- set 2- basic concepts of organic chemistry58
-
Module 4.2- alcohols, haloalkanes and analysis50
-
mod 4 to practice3
-
Mod 2 to practice5
