Chemistry - Atomic structure and the periodic table Flashcards
1
Q
What are all substances made
from
A
Atoms
2
Q
What is an atom
A
The smallest part of an element that can exist
3
Q
What is the radius of an atom
A
0.1 nm (nanometres) (1 x 10-10m), it is very small
4
Q
What is the radius of the
nucleus
A
1 x 10-14 m (1/10000th of the radius of an atom)
5
Q
Where is most of the mass in an
atom located
A
In the nucleus
6
Q
What can elements be
represented as
A
Symbols
7
Q
How many elements are there
A
About 100
8
Q
Where are elements shown
A
The periodic table
9
Q
What is a compound
A
Two or more different types of atoms chemically joined together in fixed proportions
10
Q
How can compounds be separated into their elements
A
By chemical reactions
11
Q
Are the properties of a
compound the same as the
elements they are made from
A
No
12
Q
What is a mixture
A
Two or more different types of elements or compounds not chemically bonded together, the chemical properties of each substance in the mixture are unchanged
13
Q
5 ways to separate a mixture
A
Crystilisation, simple distillation, fractional distillation, chromatography and filtration
14
Q
Why are the techniques used to
separate mixtures described as
physical processes
A
As mixtures contain two or more elements or compounds not chemically combined
15
Q
Why is a lid used
chromatography
A
Stops solvent evaporating
16
Q
How does filtration work
A
Pass through filter paper, liquid passes through, insoluble particles get caught by the filter paper
17
Q
How do you carry out
crystallisation
A
Evaporation dish and heat source. Filter crystals out of the solution
18
Q
How can you get sand and salt
from a mixture of the two
A
Dissolve in water, salt is soluble, sand isn’t. Filter to remove sand, then use crystallisation
19
Q
What two processes are involved
in distillation
A
Evaporation and condensation
20
Q
Where is the hottest part in
fractional distillation
A
The bottom
21
Q
What property must the mixture
have to be able to separate by
fractional distillation
A
Each part of the mixture must have different boiling points
22
Q
What is an element
A
A substance made up of only one type of atom
23
Q
What is a molecule
A
Two or more atoms joined together e.g. O2, Cl2, H2O, CO2
24
Q
Where are the reactants found
in an equation
A
Left side
25
Where are the products found in
| an equation
Right hand side
26
What is distillation
The separating of a liquid using evaporation and then
| condensation
27
A method used to separate two
| or more liquids
Fractional distillation
28
A method used to separate the
coloured compounds in a
mixture
Chromatography
29
A method used to separate an insoluble solid from a liquid
Filtration
30
What is crystallisation
A way to separate a dissolved solid from a solution by evaporation to leave crystals of the solid
31
Before electrons were
discovered, was it thought that
atoms could be divided
no
32
Before electrons were
discovered, atoms were thought
to be what
Tiny spheres
33
What model did the discovery of
| the electron lead to
Plum pudding model
34
What was the plum pudding
| model
That the atom was a ball of positive charge with negative
| electrons embedded in it
35
What model replaced the plum
| pudding model
Nuclear model
36
What experiment led to idea
that mass of the atom was
concentrated in the centre
Alpha scattering experiment
37
What would happen with the
alpha particle experiment if the
plum pudding model was correct
Expect particles to pass straight through or slightly deflected
38
What was observed in the alpha
| scattering experiment
Most of the particles passed through
Some deflected more than expected
Very few deflected backwards
39
What charge are alpha particles?
Positively charged
40
Explain the observations of the alpha scattering experiment
Most of the particles passed through = atom is mostly empty space
Some deflected more than expected = alpha particles hit a positively charged centre and repelled
Very few deflected backwards = alpha particles hit a concentrated mass
41
Describe the nuclear model
has a positively charged nucleus, most of the atom is empty space
42
What sub atomic particle was
| discovered first
Electron
43
Who led to the idea that
| electrons are in orbitals/shells
Niels Bohr
44
What order where the sub
| atomic particles discovered
Electron, proton the neutron
45
Who provided evidence for the
existence of neutrons within the
nucleus
Chadwick (about 20 years after the nucleus idea was
| accepted)
46
What are the differences
between the plum pudding
model and the nuclear model
Plum - single ball of positive charge spread throughout,
electrons in embedded, no nucleus, no neutrons
nuclear - positive centre/nucleus, electrons in fixed positions, has a nucleus, has neutron
47
What did Bohr suggest about the arrangement and movement of electrons
Electrons orbit the nucleus in shells that are a fixed distance
from the nucleus. Electrons can only be found in these shells
48
What particle was discovered as the nucleus was found to be
| positive
Proton
49
Name the three sub atomic particle
Proton, neutron & electron
50
What is the relative charge of a
| proton
1+
51
What is the relative charge of a
| neutron
0
52
What is the relative charge of an
| electron
-1
53
Why do atoms have no overall
electrical charge (are neutral)
The number of positive proton equals the number of negative electrons so charges cancel out
54
What does the atomic number
| tell you
number of protons
55
What makes an atom of an
| element the element it is
The protons, e.g. If an atom has 8 protons, it must be oxygen
56
What makes atoms of elements different to each other
different amount of protons
57
What is the relative mass of a
| proton
1
58
What is the relative mass of a
| neutron
1
59
What is the relative mass of an
| electron
Very small
60
What is mass number
The sum of the protons and neutrons in an atom
61
What is an isotope?
The same element but with the same number of protons but different numbers of neutrons
62
Why is the relative atomic mass of chlorine not a whole number
Has more than one isotope
63
How do the chemical properties of an isotope differ
Doesn't - has have the same number of electrons
64
How do you work out the number of protons
Use the atomic (proton) number
65
How do you work out the number of electrons in an atom
Same as the protons
66
How do you work out the number of neutrons
Mass number - atomic number
67
What is relative atomic mass
The average value that takes account of the abundance of the isotopes of an element
68
What do the electrons occupy in
| an atom
lowest energy available
69
How many electrons are there found in shells 1, 2 & 3
2,8,8
70
What sub atomic particle is involved in bonding (chemical
| reactions)
electrons
71
What holds atoms of elements
| together in compounds
Chemical bonds
72
What holds atoms of elements
| together in compounds
Chemical bonds
73
How were early periodic tables
| arranged (Newland and Mendeleev)
By atomic weights (as protons, neutron and electrons were not discovered)
74
What did Newland do wrong
Put more than one element in a box
Followed a strict order of atomic weight
His pattern eventually broke down
He didn't leave any gaps for undiscovered elements which led to elements being place in inappropriate groups
75
What is the name of the
| scientist who first published the periodic table
Dmitri Mendeleev
76
What did Mendeleev do to solve
| the problem of elements not in the correct groups
He left gaps for undiscovered elements
He was able to predict the properties of these AND was
correct
77
How is the modern periodic
| table ordered?
In order of atomic number (protons)
78
What are elements with similar
| properties place in
Groups (columns)
79
What do all elements in the
| same group have in common?
The same number of electrons in their outer shell
80
How is the modern periodic
| table arranged
Atomic number (protons) with elements in the same group as their outer number of electrons
81
What is the name given to the
| columns on the periodic table
Group
82
rows of the periodic table
Periods
83
What does the group number of
| an element tell you
The number of electron in its outer shell/ energy level
84
What does the period number of an element tell you
Number of energy levels the atom has
85
How many groups are there on the periodic table
8
86
How are the metals and non-metals arranged in the periodic table
Metals are on the left hand side and metals on the right
87
What is an ion
A charged particle
88
What types of ions do metals
| form
Positive, as they lose electrons to get a full outer shell
89
What types of ions do non-
| metals form
Negative, as they gain electrons to get a full outer shell
90
What elements are founds in the
block of the periodic table
between groups 2&3
Transition metals
91
What are the elements in group
| 0 called
Noble gases
92
Why are Noble gases unreactive/inert
As they have a full outer shell so their atoms have stable
electron arrangements (He-2, all others-8)
93
What happens to the boiling
point of the Noble gases as you
go down the group
Increases, as relative atomic mass increases so stronger
| intermolecular forces
94
What does monoatomic mean
| Noble gases
Exist as atoms
95
What are the elements in group
| 1 called
Alkali metals
96
How many electrons do all group 1 elements have in their outer
shell
1
97
Why do the metals in group 1
| have similar properties
All have 1 electron in their outer shell
98
What happens to the melting
| point as you down group 1
Decreases
| Due to metallic bonds becoming weaker as go down the group
99
What happens to the reactivity
of the group 1 metals as you go
down the group
Increases
100
Why do the alkali metals
become more reactive as you go
down the group
Increase in number of electrons/electron shells,
outer electron is further from the nucleus
so is less attracted to the positive nucleus
so easier to lose an electron
101
Give three characteristics of
| alkali metals
Metals, soft, highly reactive
102
What are the products when a
group 1 metals reacts with
water
Metal hydroxide and hydrogen
103
What is the word equation for
the reaction of sodium with
water
Sodium + water sodium hydroxide + hydrogen
104
What is the balanced symbol equation of sodium with water
2Na + 2H2O —> 2NaOH + H2
105
What observations do you see
when an alkali metal reacts with
water?
Alkali metals float on water = less dense than water
alkali metals fizz = hydrogen gas released
universal indicator (if added) goes purple = alkali produced aka metal hydroxide
metal dissolves = metal reacting to produce metal hydroxide (aq)
Reactions become more vigorous as go down group 1
106
What is observed when lithium
| reacts with water
Floats, moves on the surface, fizzes
107
What is observed when sodium
| reacts with water
Floats, forms a ball, moves on the surface, fizzes, can see a yellow flame
108
What is observed when
| potassium reacts with water
Floats, forms a ball, moves on the surface, fizzes, a lilac
| flame
109
What is formed when alkali
| metals react with oxygen
Metal oxide
110
What is the word equation for
the reaction of sodium with
oxygen
Sodium + oxygen sodium oxide
111
What is the symbol equation for the reaction of sodium with oxygen
4Na + O2 —> 2Na2O
112
What observations do you see
when lithium reacts with
oxygen?
Red-tinged flame
Bright flame in oxygen
White solid formed
113
What observations do you see
when sodium reacts with
oxygen?
Yellow-orange flame
Brighter flame in oxygen
White solid formed
114
What observations do you see
when potassium reacts with
oxygen?
Lilac flame
Even brighter flame in oxygen
White solid formed
115
What is formed when alkali
| metals react with chlorine
A metal halide is formed e.g. Sodium chloride
116
What is the word equations for
the reaction of sodium with
chlorine
Sodium + chlorine sodium chloride
117
What is the symbol equation for
the reaction of sodium with
chlorine
2Na + Cl2 2NaCl
118
What observations do you see
when group 1 elements react
with chlorine?
Bright flame
| White solid
119
What are the elements in group
| 7 called
Halogens
120
How many electrons do all
groups 7 elements have on their
outer shell
7
121
What state is chlorine at room
| temperature and its colour?
Yellow/ green gas
122
What state is bromine at room
| temperature and its colour?
Brown liquid
123
What state is iodine at room
| temperature and its colour?
Purple solid
124
Three properties of the halogens are
Non-metals,
very reactive,
diatomic (exist as molecules),
melting points and boing points increase down the group
(links with change of states as go down the group)
125
What is the charge on a halide
| ion
-1, as lose one electron to get a full outer shell
126
What happens to the reactivity
of the group 7 halogens as you
go down the group
Decreases
127
Why do the halogens become
less reactive as you go down the
group
Increase in number of energy levels,
outer shell of electrons are further from the nucleus
so less attraction between outer electrons and nucleus
so harder to gain and attract a new electron
128
What sort of compounds do
halogens form with other non
metals
Covalent
129
What sort of compounds do
| halogens form with metals
Ionic
130
What sort of molecules do all
| halogen form
Diatomic, go round in pairs
131
What is a displacement reaction
When a more reactive element displaces (kicks out) a less reactive element, so more reactive halogen (higher up the group) can kick out a less reactive halogen from an aqueous solution of its salt
132
A word equation to show the
displacement reaction between
chlorine and sodium bromide
Chlorine + sodium bromide bromine + sodium chloride
133
A symbol equation to show the
displacement reaction between
chlorine and sodium bromide
Cl2 + 2NaBr Br2 + 2NaCl
134
where are the transition metals found in the periodic table
in the centre, between groups 2 and 3
135
Compare properties of transition metals to alkali
higher melting point,
higher density,
stronger,
harder
136
how does the reactivity of the transition metals compare to the reactivity of alkali metals
less reactive
137
what are the properties of transition metals
can form different charged ions
form coloured compounds
useful as catalysts
138
what property of transition metals is an important industrial use
used as catalysts to speed up reactions
