Atomic Structure and the Periodic Table Flashcards
(101 cards)
1
Q
What is in the nucleus?
A
Protons and Neutrons
2
Q
Electrons _____ the nucleus in ______ ____
A
Orbit
Electron shells
3
Q
Atoms have the same number of _______ and _______
A
Protons
Electrons
4
Q
Why do atoms have no charge?
A
The positive charge of the protons cancel out the negative charge of the electrons
Neutrons have no charge
5
Q
Mass of neutron:
A
1
6
Q
Mass of proton:
A
1
7
Q
Mass of electron:
A
Very small 0.000000005
8
Q
Charge of proton:
A
+1
9
Q
Charge of neutron:
A
0
10
Q
Charge of electron:
A
-1
11
Q
What is the mass number of an element?
A
The total number of protons and neutrons in the nucleus of the atom
12
Q
What is the atomic number of an element?
A
The number of protons in the nucleus of the element
13
Q
What are isotopes?
A
Different forms of an element, that have the same number of protons but a different number of neutrons
14
Q
What is a compound?
A
A substance made from 2 or more elements that are chemically bonded
15
Q
What is needed to separate compounds into its original elements?
A
A chemical reaction
16
Q
What is a mixture?
A
Elements that are mixed together - no chemical reaction
17
Q
Can a mixture be seperated out?
A
Yes by physical methods
18
Q
Properties of ________ are usually different from the properties of the ________ element
A
Compounds
Original
19
Q
Properties of ________ are a mix of the properties of the ________
A
Mixtures
Elements
20
Q
What is chromatography used to separate?
A
Mixtures (of coloured compounds such as dyes)
21
Q
What is the solvent?
A
The liquid
22
Q
Why use a pencil to mark during chromotography?
A
Its insoluble
23
Q
Why should the compounds NOT touch the solvent?
A
The compounds will dissolve in it
24
Q
What will the movement of a dye be if its insoluble?
A
It will stay on the baseline
25
What is filtration used to separate?
Insoluble solids from liquids
26
What is evaporation used to separate?
Solids from solutions
27
What dish is used during evaporation?
An evaporating dish
28
What is crystallisation used to separate?
Soluble solids from solutions if the salt decomposes when heated
29
When does evaporation not work?
If the salt decomposes when heated
30
During crystallisation what do you do after evaporating the solution to form salt crystals?
Filter the crystals out of the solution
31
How do you separate rock salt?
Dissolve the salt in water
Filter the mixture - removes rock
Evaporate the water - leaves salt as crystal
32
What is distillation used to separate?
Mixtures which contain liquids
33
What is simple distilliation used to separate?
A liquid from a solution
34
What is fractional distillation used to separate?
A mixture of liquids (more than 1)
35
Simple distillation can only be used to separate things with .......
Very different boiling points
36
What happens during simple distillation?
The solution is heated - liquid with lowest boiling point evaporates
Vapour is cooled by a condenser and collected
37
What happens during fractional distillation?
Heat the mixture
Different liquids evaporate at different temps
When one liquid evaporates at its boiling point, it will reach the top of the column
Other liquids that start evaporating will only get a certain way before condensing
38
John _______ said that all matter was made up of ______ which are _____ ______
Dalton
Atoms
Solid spheres
39
What did JJ Thompson conclude?
The plum pudding model
40
Who thought of the plum pudding model?
JJ Thompson
41
What is the plum pudding model?
That an atoms a ball of positive charge with negatively charged electrons stuck inside it
42
Who conducted the alpha particle scattering experiment?
Ernst Rutherford
43
What did Ernst Rutherford do?
He fired positively charged alpha particles at a thin sheet of gold
44
What was assumed would happen in the alpha particle scattering experiment?
That particles would pass through the sheet or be slightly deflected at most
45
What actually happened in the alpha particle scattering experiment?
Some particles were deflected more than expected and a small number were deflected backwards while most did go straight through
46
How is the nuclear model used to explain the alpha particle scattering experiment?
The atom has a tiny positively charged nucleus at the centre, where most of the mass is concentrated
A 'cloud' of negatively charged electrons surround the nucleus with most of the atom being empty space
47
Why were some particles deflected backwards in the alpha particle scattering experiment?
Because, when the alpha particles came near the concentrated positive charge of the nucleus, they repelled (alpha particle is positively charged)
48
What did Neils Bohr realise?
That if there is a 'cloud' of electrons, the electrons would be attracted to the nucleus, causing the atom to collapse
49
What did Neils Bohr suggest?
That electrons orbit the nucleus in fixed shells
50
Who suggested that electrons orbit the nucleus in fixed shells?
Niels Bohr
51
Who discovered the nucleus?
James Chadwick
52
How many electrons can go in each shell?
2
8
8
53
Atoms want to have a ___ outer shell of electrons
Full
54
Who had the atomic theory (periodic table)?
John Dalton
55
Who decided to group elements into Traids?
Johann Dobereiner
56
How did Johann Dobereiner group elements?
He grouped them into triads, based on similar appearance and reactions
57
Who decided to group elements into the Law of Octaves?
John Newlands
58
How did John Newlands group elements?
He grouped them into the Law of Octaves, in the order of their relative atomic mass
59
Who arranged the Table of Elements?
Dimitri Mendeleev
60
How did Mendeleev order elements?
In order of increasing atomic weight but switched and placed some out of order to appear in the same column as other elements with similar properties
61
Why did Mendeleev reorder some elements?
So that elements would be in the same column as other elements with similar properties
62
Why did Mendeleev leave spaces?
For atoms that are yet to be discovered - gaps allowed Mendeleev to predict the properties of these undiscovered elements
63
What discovery confirmed that Mendeleev was correct to not place elements in a strict order of atomic mass?
Isotopes
64
What did the discovery of isotopes confirm?
That Mendeleev was correct to not place elements in a strict order of atomic mass
65
What are atoms in order of in the modern periodic table?
Increasing atomic (proton) mass
66
What does the group number tell?
How many elements there are in the outer shell
67
What does the way atoms react depend on?
How many electrons there are in the outer shell, groups reacts similarly
68
Properties of metals:
Strong
Malleable
Good conductors of heat and electricity
High melting and boiling points
69
Properties of non-metals:
```
Dull
Brittle
Not always solid at room temp
Don't generally conduct
Generally have a lower density
```
70
What are unique about transition metals?
They can have more than one ion
They are often coloured so compounds that contain them are colourful
They often make good catalysts
71
What are Group 1 metals called?
Alkali metals
72
Properties of alkali metals:
Soft
| Low density
73
As you go down Group 1:
Higher relative atomic mass
Lower melting and boiling points
Increasing reactivity
74
Why does the reactivity of alkali metals increase as you go down the group?
The outer electron is lost more easily as the attraction between the outer shell electron and the nucleus decreases because the electron is further away from the nucleus as you go down the group, meaning there is more electron shielding, so not as much energy is needed to lose the other electron to form a full outer shell
75
What do alkali metals react with?
Non-metals
76
What do alkali metals form when they react with non-metals?
Ionic compounds
77
What colour solution is generally formed when alkali metals when dissolves in water?
Colourless
78
Alkali metals react ________ with water
Vigorously
79
What is produced when alkali metals react with water?
Hydrogen gas and metal hydroxides
80
What solutions do metal hydroxides produce when dissolved in water?
Alkaline
81
Alkali metals react ________ with chlorine
Vigorously
82
What is formed when alkali metals are heated in chlorine gas?
White metal chloride salts
83
What is formed when alkali metals react with oxygen?
A metal oxide
84
Alkali metals burn with a ________ flame when reacted with oxygen
Coloured
85
Compared to transition metals, alkali metals...
Are less dense, strong and hard
| Have lower melting points
86
How many electrons are there in the outer shell of halogens?
7
87
`As you go down Group 7:
Higher melting and boiling points
Higher relative atomic mass
Less reactive - harder to gain an extra electron - outer shell is further away
88
Why does the reactivity decrease as you go down Group 7?
Because the outer electron shell is further away from the nucleus, meaning there is more electron shielding, meaning it is harder to attract an electron to the nucleus
89
How do halogens share electrons?
Via covalent bonding
90
How do halogens achieve a full outer shell?
They share electrons with other non-metals via covalent bonding
91
What kind of compounds are formed when halogens react with non metals?
Compounds with simple molecular structures
92
What charge ions do halogens form when they bond with metals?
1- ions
93
What kind if compound is formed when metals and halogens bond?
Ionic compounds
94
What are group 0 elements also called?
Noble gases
95
Properties of noble gases:
Inert - unreactive
| Colourless
96
Why are noble gases inert?
They have a full outer shell that is energetically stable so they don't need to gain or lose electrons
97
Noble gases exist as _________ gases
Monatomic
98
What are monatomic gases?
Single atoms not bonded to each other
99
Why are noble gases colourless and non-flammable?
Because they are inert
100
What is the trend in the boiling point of noble gases?
It increases as you go down the group
101
Why does the boiling point of noble gases increase as you go down the group?
Because there is an increase in the number of electrons in each atom, meaning there are greater intermolecular forces that have to be overcome
