1
Q
who invented the periodic table?
A
Dmitri Mendeleev
2
Q
how many elements are there?
A
about 100 (118)
3
Q
groups (vertical columns) indicate what?
A
the number of electrons in the outer shell of an element
4
Q
what do the periods indicate?
A
the number of shells an atom has
5
Q
why do elements of the same group have similar properties?
A
they have the same number of electrons in their outer shell
6
Q
how many electrons do group 2 elements have in their outer shell?
A
2
7
Q
group 1 elements are…
A
alkali metals
8
Q
group 7 elements are…
A
halogens
9
Q
group 0 elements are…
A
noble gases
10
Q
what do the properties of elements depend on?
A
the number of electrons they have in their outer shell
11
Q
how are electrons arranged in the shells?
A
they always fill the first shell first
12
Q
how to figure out the electronic configuration of an atom?
A
- the atomic number indicates the number of protons and therefore electrons
- the period indicates the number of shells of an atom
- e.g nitrogen has 7 electrons and is found in period 2 so its electronic configuration is 2,5
13
Q
find the electronic configuration of sodium using groups and periods
A
- sodium is in period 3, so it has 3 shells occupied
- the first 2 shells must be full (2,8)
- sodium is in group 1 so it has 1 electron in its outer shell
- 2,8,1
14
Q
what can elements be classified as?
A
metals and non-metals
15
Q
metals are found on..
A
the left hand side of the periodic table
16
Q
non metals are found on the..
A
right hand side of the periodic table
17
Q
where are metals and non-metals separated?
A
they are separated by a zig-zag going from Boron to Astatine
18
Q
properties of metals
A
- metals conduct electricity because they allow charge to pass through them easily
- metal oxides are basic (they will neutralise acids)
- metal oxides which dissolve will form solutions with a pH of more than 7
19
Q
non-metals
A
- poor conductors of electricity
- non-metal oxides are acidic (they will neutralise bases)
- they dissolve in water to form solutions with a pH of less than 7
20
Q
group 0
A
- noble gases are all inert, colourless gases
- inert - don’t react with much at all
21
Q
why are noble gases inert?
A
it takes a lot of energy to add or remove electrons from a noble gas atom
22
Q
ionic bonding
A
- atoms lose or gain electrons and become ions
- the oppositely charged ions are strongly attracted to one another by electrostatic attractions
23
Q
simple ions form when…
A
atoms lose or gain electrons
24
Q
negative ion
A
anion - gain electrons
25
positive ion
cation - lose electrons
26
ions
are charged particles
- can be single atoms or groups of atoms
27
the number of electrons lost or gained is the same as...
...the charge on the ion
28
if two electrons are lost...
the charge is 2+
29
if 3 electrons are gained...
the charge is 3-
30
how do metals become ions?
- they lose electrons to form positive ions (cations)
- they are in group 1,2 and 3
31
what type of ion do metals become?
cations (positive ions)
32
what type of ion do non-metals become?
anions (negative ions)
33
how do non-metals become ions?
- they gain electrons to form negative ions (anions)
- they are in group 5,6 and 7
34
what structure do ionic compounds have?
a closely packed lattice structure
35
how do group 1 elements form ions?
they lose 1 electron and become 1+ cations
36
how do group 2 elements form ions?
they lose 2 electrons and become 2+ ions
37
how do group 3 elements form ions?
they lose 3 electrons and become 3+ cations
38
how do group 5 elements form ions?
they gain 3 electrons and become 3- anions
39
how do group 6 elements form ions?
they gain 2 electrons and become 2- anions
40
ammonium
NH₄⁺
41
hydroxide
OH¯
42
nitrate
NO3-
43
sulfate
SO₄²-
44
carbonate
CO₃²⁻
45
hydrogen ion
H+
46
silver ion
Ag+
47
copper ion
Cu²⁺
48
iron ion
Fe2+
49
how many diatomic elements are there?
7
50
what are the diatomic elements?
- hydrogen
- nitrogen
- oxygen
- fluorine
- chlorine
- bromine
- iodine
51
can ionic compounds conduct electricity?
- they cant conduct electricity when they are solid
- they are able when tehy are melted or dissolved
52
why do ionic compounds have hight melting and boiling points?
the electrostatic attraction between the oppositely charged ions is very strong, and a lot of energy is needed to overcome the strong attraction
53
covalent bonding
atoms bond by sharing pairs of electrons
54
what is the force of attraction that forms covalent bonds?
strong electrostatic attraction between the negatively charged shared electrons (bonding pair) and the positively charged nuclei of the atoms
55
how are the elements arranged in the periodic table?
by atomic number
56
what is the name given to the rows in the periodic table?
Periods
57
what is the name given to the columns in the periodic table?
groups
58
name the type of structure that ionic compounds have
giant ionic lattice
59
which non-metal element can conduct electricity?
graphite
60
why can graphite conduct electricity?
only 3 of each carbons 4 outer electrons are used in bonds, so each carbon atom has 1 electron that's delocalised
61
what is the overall charge of an ionic compound?
zero (neutral)
62
how are ions held together in a giant ionic lattice?
by the attraction between oppositely charged ions
63
why do ionic compounds have high melting and boiling points?
because a lot of energy is needed to overcome the strong attraction between the oppositely charged ions
64
give 3 examples of noble gases
helium
neon
argon
65
what does the group to which an element belongs correspond to?
the number of electrons it has in its outer shell
66
why do elements of the same group have similar properties?
because they all have the same number of electrons in their outer shell
67
why do metals and non-metals react together?
because metals become cations and non-metals become anions, and the oppositely charged particles re
68
what attraction results in ionic bonds?
electrostatic forces of attraction
69
what is the overall charge of an ionic compound?
zero
70
do ionic compounds conduct electricity?
no, but if you melt them or dissolve them in water they are able to conduct electricity
71
why does graphite have a high melting point?
the covalent bonds in the layers need loads of energy to break
72
is C60 a giant covalent structure?
no, it is made up of large covalent molecules
72
what are C60 fullerene molecules?
hollow spheres made up of 60 carbon atoms
73
why is C60 fullerene solid at room temperature?
because it is a large molecule, so the intermolecular forces between the molecules are strong
74
what are C60 molecules held together by?
by intermolecular forces, so they can slide over each other, so it is soft
75
why is C60 fullerene a poor conductor of electricity?
the delocalised electron of each carbon atom can't move between the molecules
76
why does diamond not conduct electricity?
it has no free electrons or ions
Chemistry IGCSE
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