Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry > Key Concepts > Flashcards

Key Concepts Flashcards

(84 cards)

Start Studying
1
Q

Three ideas in John Daltons theory about the atom

A

Atom cannot be created, divided or destroyed

Atoms of the same element are exactly the same and atoms of different elements are different

Atoms join with other atoms to make new substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What discovery caused the original dalton model of an atom to change

A

The discovery of subatomic particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How did JJ Thomson discover the electron

A

Thomson experimented with a cathode ray tube

The beam moved towards the positively charged plate so he knew that the particles must have a negative charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Atomic model proposed by JJ Thomson

A

Plum pudding model

Negatively charged electrons scattered through a positively charged material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What did Ernest Rutherford discover from his gold foil experiment

A

He shot a beam of positively charged particles at a sheet of gold foil

Most of the particles passed straight through suggesting that atoms were mostly empty space.
A few particles were deflected and a few bounced directly back showing there must be a tiny, dense and positively charged nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Rutherfords model of the atom

A

Mass is concentrated in the central nucleus
Mostly empty space
Electrons travel in random paths around the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Structure of an atom

A

Small central nucleus made up of protons and neutrons
Electrons orbit (move around) the nucleus in shells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the radius of the nucleus? How large is it compared to the radius atom?

A

The radius of the nucleus is 1x10^-14 m
This is 1/10000 of the atomic radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the relative masses of protons, neutrons and electrons

A

Proton : 1
Neutron : 1
Electron : 1/1836

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the relative charges of protons, neutrons and electrons

A

Proton : +1
Neutron : 0
Electron : -1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why do atoms contain equal numbers of protons and electrons

A

Atoms are stable with no overall charge

Protons are positively charged and electrons are negatively charged. For the charges to balance, the number of protons and electrons must be equal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is the mass of an atom concentrated

A

Nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the atomic number of an atom represent

A

The number of protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the mass number of an atom mean

A

The mass number is the number of protons and neutrons found in the nucleus of an atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Atoms of the same element have the same number of _______ in the nucleus and this is unique to that element

A

Protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is an isotope

A

Are atoms with the same number of protons (so the same element) but a different number of neutrons
Isotopes of an element have the same atomic number but different mass numbers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Boron has the atomic number 5 and the mass number 11. How man protons, electrons and neutrons does Boron have

A

5 protons
5 electrons
6 neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is the relative atomic mass not always a whole number

A

Different isotopes of the same element have different mass numbers. The relative atomic mass is an average of the masses of all these isotopes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What 2 values would be required to calculate the relative atomic mass of chlorine

A

Mass numbers and relative abundances of all the isotopes of chlorine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How did Mendeleev arrange the elements in his periodic table

A

Elements arranged with increasing atomic masses
Elements with similar properties put into groups
Switched the position of some elements
Gals left for undiscovered elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How was Mendeleev able to predict the properties of new elements

A

He left gaps in his table. He used the properties of elements next tot these gaps to predict the properties of undiscovered elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Mendeleev’s table lacked some amount of accuracy in the way he’d ordered his elements. Why was this?

A

Isotopes were poorly understood at the time
Protons and neutrons had not yet been discovered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How are elements arranged in the modern periodic table

A

In order of increasing atomic number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Elements in the same group have similar _______ ________

A

Chemical properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Why do elements in the same column have similar chemical properties
Same number of outer shell electrons Number of outer shell electrons determines how an atom reacts
26
What does the period (row) number tell you about all the elements in that period
Elements in the same period have the same number of electron shells E.g all elements in period four have four shells of electrons
27
What does group (column) number tell you about all the elements in that group
All elements in the same group have the same number of outer electrons E.g all elements in group 2 have 2 electrons in their outer shell
28
On which side of the periodic table are the metals positioned
Left hand side
29
What determines where an element is a metal or non metal
Atomic structure of the elements
30
What is the maximum number of electrons allowed in each of the first 3 shells
1st shell - 2 2nd shell - 8 3rd shell - 8
31
When are atoms most stable
When they have full electron shells
32
The atomic number of Na is 11 What is the electron configuration of Na
2, 8, 1
33
What is an ionic bond
A bond between a metal and non-metal involving the transfer of electrons
34
In terms of electrons, describe what happens to the metal and non-metal when an ionic bond forms
The metal atom loses electrons to become a positively charged ion (cation) The non-metal gains electrons to become a negatively charged ion (anion)
35
What is a cation
A positively charged ion
36
What is an anion
A negatively charged ion
37
What is an ion
An atom or group of atoms with a positive or negative charge
38
If an ion is positively charged, has it lost or gained electrons
It has lost electrons. There are fewer negatively charged electrons to cancel out the charge of the.positive protons. This means the overall charge becomes positive
39
Why do elements in groups 1,2,6 and 7 readily form ions
So they become more stable and achieve the electron structure of the noble gases (group 8)
40
What type of ions do elements in group 1 and 2 form
Cations (positive) Group 1 metals will form 1+ ions Group 2 metals will form 2+ ions
41
What type of ions do elements in groups 6 and 7 form
They are non-metals so form anions (negative) Group 6 will form 2- ions Group 7 will form 1- ions
42
What does it mean is an ionic compound ends in -ide
The compound contains 2 elements
43
What does it mean if an ionic compound ends in -ate
The compound contains at least three elements, one of which is oxygen
44
Structure of an ionic compound
Lattice structure Regular arrangement of ions Ions held together by strong electrostatic forces between ions with opposite charges
45
What is a covalent bond
A bond formed when an electron pair is shared between two atoms
46
What forms as a result of covalent bonding
A molecule
47
Are covalent bonds weak or strong
Strong
48
Which is smaller, an atom or a molecule
An atom. Simple molecules consist of atoms joined by a string covalent bonds within the molecule
49
Why do ionic compounds have high melting points
Strong electrostatic attraction between the positive and negative ions requires a lot of energy to overcome
50
When do ionic compounds electricity? Why?
When molten or aqueous (dissolved in water) because the ions are charged and free to move, when solid, the ions are fixed in an ionic lattice so can’t move
51
Why do simple molecular compounds have low melting and boiling points
They have weak intermolecular forces (forces between molecules) which only require a little energy to overcome
52
Do simple molecular compounds conduct electricity
No because there are no charged particles
53
Do giant covalent structures have a high melting point
Yes because they have lots of strong covalent bonds with require a lot of energy to break
54
How do metals conduct electricity and heat
The positive ions are fixed in a sea of delocalised electrons. These electrons are free to move and carry charge/energy
55
True or false? Metals are insoluble in water
True
56
Name two giant covalent structures formed from carbon atoms
Graphite and diamond
57
Structure of graphite
Each carbon atom bonded to 3 other carbon atoms Layers of hexagonal rings of carbon atoms Weak intermolecular forces between layers One delocalised electron per carbon atoms
58
Describe and explain properties of graphite
Soft/slippery due to only weak intermolecular forces between layers which allow them to slide over on another Graphite conducts electricity because there is one delocalised electron per carbon atom. The delocalised electrons are mobile charges
59
Describe structure of diamond
All carbon atom are covalently bonded to four other carbon atoms No delocalised electrons
60
Properties of diamond
Very hard Very high melting point Doesn’t conduct electricity as there are no charged particles
61
Uses of graphite
Electrodes because graphite conducts electricity and has a high melting point Lubricant because it’s slippery (layers in graphite can slide over each other)
62
Why is diamond used in cutting tools
It’s very hard
63
What is fullerene
A fullerene is a molecule made of carbon, shaped like a closed tube or hollow ball
64
Two fullerenes
Graphene C60 (buckminsterfullerene)
65
Properties of C60
Slippery due to weak intermolecular forces Low melting point Spherical Strong covalent bonds between carbon atoms in a molecule Large surface area
66
Properties of graphene
High melting point due to covalent bonding between carbon atoms Conducts electricity because it has delocalised electrons
67
Why is graphene useful in electronics
It is extremely strong and has delocalised electrons which are free to move and carry charge It is only one atom thick as it is a single layer of graphite
68
What is a polymer
Long chain molecules formed from many monomers E.g poly(ethene)
69
What bond is formed between carbon atoms in polymer molecules
Covalent bonds
70
Properties of metals
High melting point High density Good conductors of electricity Malleable and ductile Generally shiny
71
Why are metals malleable
The atoms are arranged in uniform rows which can slide over one another
72
Why can metals conduct electricity
The electrons in the metal are charges that can move
73
Properties of non-metals
Low boiling points Poor conductors of electricity Brittle when solid
74
How do you calculate the relative formula mass of a compound
Add together all the relative atomic masses of atoms in the compound
75
What is the empirical formula
The smallest whole number ratio of the atoms of each elements in a compound Reacting masses of percentage composition can be used to calculate the empirical formula
76
Empirical formula of Fe2O4
FeO2
77
What is molecular formula
Actual number of atoms of each elements in a compound
78
What is the law of conservation of mass
No matter is lost or gained during a chemical reaction
79
If a reaction is carried out in a closed system, what can you say about the total mass of the reaction throughout the experiment
Mass stays constant
80
What equation links mass, moles and relative atomic mass
Mass (g) = moles x relative atomic mass (Mr)
81
How can you calculate concentration in g/dm^3
Concentration (g/dm^3) = mass (g) / volume (dm^3)
82
What is Avogadro constant
The number of atoms, molecules or ions in one mole of a given substance The value of the constant is 6.02 x 10^23
83
What formula links Avogadros constant, moles and number of particles
Number of particles = Avogadro constant x moles
84
What is a limiting reagent in a chemical reaction
The chemical that is used up first in a reaction, preventing the formation of more product. Typically, an excess of one of reactants is used to ensure that the other reactant is completely used up.

Chemistry (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions