Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GCSE - Chemistry > Topic 1 - Key Concepts In Chemistry > Flashcards

Topic 1 - Key Concepts In Chemistry Flashcards

You may prefer our related Brainscape-certified flashcards:
GCSE Geography - AQA flashcards AP® Chemistry flashcards GCSE Religious Studies - Edexcel Route B flashcards GCSE Religious Studies - Eduqas Route A flashcards GCSE Religious Studies - Edexcel Route A flashcards GCSE Religious Studies - Eduqas Route B flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What are the 3 ideas in John Daltons theory about the atom?

A
  1. Atoms cannot be created, divided or destroyed
  2. Atoms of same element are exactly the same/atoms of different elements are different
  3. 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

Discovery of subatomic particles

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

Describe structure of atom

A

Small central nucleus made up of protons and neutrons

Electrons orbit the nucleus in shells

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

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

A

Radius of nucleus is 1x10⁻¹⁴m

This is 1/10,000 of atomic radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
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
6
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
7
Q

Why do atoms contain equal numbers of protons and electrons

A

Atoms are stable with no overall charge
Protons are postively charges and electrons are negatively charged. For charges to balance, no of protons and electrons must be equal.

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

Where is the mass of an atom concentrated

A

In nucleus

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

What does atomic number of an atom represent

A

Number of protons

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

What does mass number of an atom mean

A

Mass number is number of protons and neutrons found in nucleus of atom

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

Atoms of same element have same number of ________ in 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
12
Q

Whats an isotope

A

Isotopes are atoms with same number of protons but 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
13
Q

Boron has atomic number 5 and mass number 11. How many protons, neutrons and electrons 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
14
Q

Why is relative atomic mass not always a whole number

A

Different isotopes of same element have different mass numbers. 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
15
Q

What 2 values would be requires 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
16
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 position of some elements
  • Gaps left for undiscovered elements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How was Mendeleev able to predict the properties of new elements?

A

He left gaps in his periodic table

Used properties of elements next to gaps to predict properties of undiscovered elements

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

Mendeleev’s table lacked some amount of accuracy in the way he 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
19
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
20
Q

Elements in the same group (column) have similar _______ ________

A

Chemical properties

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

Why do elements in the same column have similar chemical properties?

A

Same no of outer shell electrons

No of outer shell electrons determines how atom reacts

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

What does the period (row) number tell you about all the elements in that period?

A

Elements in the same period have the same number of electron shells

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

What does group (column) number tell you about all the elements in that group

A

All elements in same group have same number of outer shell electrons

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

On which side pf periodic table are metals positioned?

A

Left side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What determines whether an element is a metal or non metal?

A

Atomic structure of the elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Whats the max number pf electrons allowed in each of first three shells

A

1st shell - 2

2nd + 3rd shell - 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

When are atoms most stable

A

When they have full electron shells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The atomic number of Na is 11.

Whats the electronic configuration of Na?

A

2, 8, 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How is electron configuration of an element related to its position in the periodic table?

A

Diagram: no of rings is period, no of electrons in outer ring is group, total no of electrons is atomic number
Number: (eg sodium 2.8.1) sodium has three shells as there are 3 numbers, last number is no of outer shell electrons/group, sum of digits is atomic number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Whats an ionic bond?

A

A bond between a metal and non metal involving transfer of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

In terms of electrons, describe what happens to the metal and non metal when an ionic bond forms

A

Metal atom loses electrons to become a positively charged ion (cation)
Non metal gains electrons to become a negatively charged ion (anion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Whats an ion

A

An ion is an atom or group of atoms with a positive or negative charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

If an ion is positively charged, has it lost of gained electrons?

A

Lost. There are fewer negatively charged electrons to cancel out the charge of the positive protons so overall charge becomes positive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Na⁺ has atomic no 11 and mass no 23. How many protons, neutrons and electrons are in this ion?

A

11 protons
10 electrons
12 neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

O²⁻ has atomic no 8 and mass no 16. How many protons, neutrons and electrons are in this ion?

A

8 protons
10 electrons
8 neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why do elements in groups 1,2,6 and 7 readily form ions?

A

So they become more stable and achieve the electron structure of the noble gases (group 8)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What type of ions do elements in group 1 and 2 form?

A

Cations (positive)
Group 1 metals form 1+ ions
Group 2 metals form 2+ ions

38
Q

What type of ions do elements from groups 6 and 7 form?

A

Non metals so form anions (negative)
Group 6 forms 2- ions
Group 7 forms 1- ions

39
Q

What does it mean if an ionic compound ends in -ide?

A

Compound contains 2 elements

40
Q

What does it mean if an ionic compound ends in -ate?

A

The compound contains at least 3 elements, one of which is oxygen

41
Q

Describe the structure of an ionic compound

A

Lattice structure
Regular arrangement of ions
Ions held together by strong electrostatic forces between ions with opposite charges

42
Q

Whats the chemical formula of sodium oxide, formed from Na⁺ and O²⁻ ?

A

Na₂O

Charges must balance so 2 sodium ions are required

43
Q

Whats the chemical formula of magnesium hydroxide, formed from Mg²⁺ and OH⁻ ?

A

Mg(OH)₂

Charges must balance so 2 hydroxide ions are required

44
Q

What is a covalent bond?

A

A bond formed when an electron pair is shared between 2 atoms

45
Q

What forms as a result of covalent bonding?

A

A molecule

46
Q

True or false? ‘Covalent bonds are weak’

A

FALSE

Covalent bonds are strong

47
Q

Which is smaller, an atom or a molecule?

A

An atom

Simple molecules consist of atoms joined by strong covalent bonds within the molecule

48
Q

Why do ionic compounds have high melting points?

A

Strong electrostatic attraction between the positive and negative ions requires a lot of energy to overcome

49
Q

When do ionic compounds conduct electricity? Why?

A

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 cant move.

50
Q

Why do simple molecular compounds have low melting and boiling points?

A

They have weak intermolecular forces (forces between molecules) which only require a little energy to overcome

51
Q

Do simple molecular compounds conduct electricity? Why? Why not?

A

No because there are no charged particles

52
Q

Do giant covalent structures have a high melting point? Explain your answer.

A

Yes because they have lots of strong covalent bonds which require a lot of energy to break

53
Q

How do metals conduct electricity and heat

A

The positive ions are fixed in a sea of delocalised electrons. These electrons are free to move and carry charge/energy.

54
Q

True or false? ‘Metals are insoluble in water’

A

TRUE

55
Q

Name two giant covalent structures formed from carbon atoms

A

Diamond

Graphite

56
Q

Describe the structure of graphite

A
  • 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 atom
57
Q

Describe and explain the properties of graphite

A

Soft/slippery because of weak intermolecular forces between layers - allow to slide over each other
Conducts electricity because theres one delocalised electron per carbon atom. These electrons are mobile charges

58
Q

Describe structure of diamond

A

All carbon atoms are covalently bonded to 4 other carbon atoms
No delocalised electrons

59
Q

Describe properties of diamond

A

Very hard
Very high melting pt
Doesnt conduct electricity as are no charged particles

60
Q

What are the uses of graphite? Why?

A

Electrodes because graphite conducts electricity and has high melting pt
Lubricant because its slippery

61
Q

Why is diamond used in cutting tools

A

Very hard

62
Q

Whats a fullerene?

A

A molecule made of carbon, shaped like a closed tube or hollow ball

63
Q

Name 2 fullerenes

A

Graphene

C₆₀ (buckminsterfullerene)

64
Q

What are the properties of the fullerene C₆₀ ?

A

Slippery due to weak intermolecular forces
Low melting pt
Spherical
Strong covalent bonds between carbon atoms in a molecule
Large surface area

65
Q

What are the properties of graphene?

A

High melting pt due to covalent bonding between carbon atoms

Conducts electricity because it has delocalised electrons

66
Q

Why is graphene useful in electronics

A

Is extremely strong and has delocalised electrons - are free to move and carry charge
One one atom thick as it is a single layer of graphite

67
Q

What is a polymer? Name one

A

Long chain molecules formed from many monomers

Polyethene

68
Q

What bond is formed between carbon atoms in polymer molecules?

A

Covalent bonds

69
Q

What are the properties of metals?

A 
High melting pt
High density
Good conductors of electricity
Malleable and ductile
Generally shiny
70
Q

Explain why metals are malleable

A

Atoms are arranged in uniform rows which can slide over one another

71
Q

Explain why metals can conduct electricity

A

Electrons in metal are charges that can move

72
Q

What are the properties of non metals

A

Low boiling pt
Poor conductors of electricity
Brittle when solid

73
Q

List the limitations of the following models when representing ionic compounds: dot and cross, 2D and 3D diagrams

A

Dot and cross- no lattice structure or ionic bonds
2D- only shows one layer, doesnt show formation of ions
3D- shows spaces between ions, doesnt show charges

74
Q

List the limitations of the following models when representing covalent molecules: dot and cross and ball and stick

A

Dot and cross- doesnt show relative sizes of atoms or intermolecular forces
Ball and stick- bonds shown as sticks rather than forces, doesnt show how covalent bonds form

75
Q

How do you calculate the relative formula mass of a compound?

A

Add together all the relative atomic masses of the atoms in the compound

76
Q

Whats the empirical formula? What 2 values could be used to calculate the empirical formula of a simple compound?

A

The smallest whole number ratio of the atoms of each element in a compound
Reacting masses or percentage composition can be used to calculate the empirical formula

77
Q

Whats the empirical formula for Fe₂O₄ ?

A

FeO₂

78
Q

Whats the molecular formula?

A

Actual number of atoms of each element in a compound

79
Q

Describe an experiment to work out the empirical formula of magnesium oxide

A
  • weigh sample of magnesium
  • heat sample in crucible
  • weigh mass of magnesium oxide at end
  • calculate mass of oxygen
  • calculate moles of magnesium and oxygen using the experimental mass and relative atomic mass
  • work out whole number ratio to number of moles of magnesium to oxygen
80
Q

What is the law of conservation of mass

A

No matter is lost or gained during a chemical reaction

81
Q

If a reaction is carried out in a closed system, what can you say about the total mass od the reaction throughout the experiment?

A

Mass stays constant

82
Q

If a reaction is carried out in an open flask and a gas is produced, what can you say about the total mass of the reaction throughout the experiment?

A

Mass decreases as gas escapes

83
Q

52g of calcium reacts with oxygen to form 79g of calcium oxide. Using the law of conservation of mass, what mass of oxygen is needed?

A

79-52=27

Mass of oxygen = 27g

84
Q

What equation links mass, moles and relative atomic mass?

A

Mass (g) = moles x relative atomic mass (Mr)

85
Q

How can you calculate concentration in g/dm³ ?

A

Concentration (g/dm³) = mass (g) / volume (dm³)

86
Q

What is the avogadro constant?

A

Number of atoms, molecules or ions in one mole of a given substance
Value of constant is 6.02 x 10²³

87
Q

Whats the mass of 20 moles of calcium carbonate, CaCO₃

A

Mass (g) = moles x relative atomic mass (Mr)
Mr = 100
20 x 100 = 2000g

88
Q

What formula links the avogadro constant, moles and no of particles?

A

No of particles = avogadro constant x moles

89
Q

How many atoms are in 3 moles of copper?

A

No of atoms = avogadro constant x moles

  1. 02 x 10²³ x 3
  2. 81 x 10²⁴
90
Q

Whats a limiting reagent in a chemical reaction?

A

The chemical thats 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.

GCSE - Chemistry (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions