Topic 1: Atomic Structure Flashcards

1
Q

What did Robert Boyle propose in 1663?

A

He proposed that there were some substances that could not be made simpler. These were the chemical elements as we now know them.

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2
Q

What did John Dalton propose in 1803?

A

He proposed that elements were composed of indivisible atoms. All of the atoms of a particular element had the same mass and atoms of different elements have different masses. Atoms could not be broken down.

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3
Q

What did Henri Becquerel discover in 1896?

A

He discovered radioactivity. This showed that particles could come from from inside the atom. Therefore the atom was not indivisible.

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4
Q

What did J.J. Thomson discover in 1897?

A

He discovered the electron. This was the first sub atomic particle to be discovered. He showed that electrons were negatively charged and electrons from all elements are the same.

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5
Q

What realisation was made from J.J. Thomson’s discovery in 1897?

A

As electrons had a negative charge, there had to be some source of positive charge inside the atom too. Also, as electrons were much lighter than whole atoms, there had to be something to account for the rest of the mass of the atom.

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6
Q

What model of the atom did J.J. Thompson propose?

A

He suggested that the electrons were located within the atom in circular arrays, like plums in a pudding of positive charge. This is commonly known as the Plum Pudding Model.

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7
Q

What did Ernest Rutherford discover in 1911?

A

He found that most of the mass and all of the positive charge of the atom was centred in a tiny nucleus.

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8
Q

What are the three fundamental particles?

A

Protons, Neutrons and Electrons.

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9
Q

What forms the nucleus of an atom?

A

Protons and Neutrons.

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10
Q

What is the collective term for protons and neutrons?

A

Nucleons, due to being found in the nucleus.

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11
Q

What is the mass of a proton?

A

1.673 x 10^-27 kg

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12
Q

What is the mass of a neutron?

A

1.675 x 10^-27 kg

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13
Q

What is the mass of an electron?

A

0.911 x 10^-30 kg

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14
Q

What is the actual charge of a proton?

A

+1.602 x 10^-19 C

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15
Q

What is the charge of a neutron?

A

0 C

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16
Q

What is the actual charge of an electron?

A

-1.602 x 10^-19 C

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17
Q

Where is the electron positioned?

A

Around the nucleus in orbitals/shells.

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18
Q

What is the relative charge of a proton?

A

+1 C

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19
Q

What is the relative charge of an electron?

A

-1 C

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20
Q

What is the relative mass of a neutron?

A

1

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21
Q

What is the relative mass of a proton?

A

1

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22
Q

What is the relative mass of an electron?

A

1/1840

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23
Q

What is the name of the force that holds the protons and neutrons together in the nucleus?

A

Strong Nuclear Force

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24
Q

What is the name of the force holding protons and electrons together?

A

Electrostatic forces of attraction

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25
Q

Why don’t protons repulse each other in the nucleus?

A

The Strong Nuclear Force overcomes the repulsion. SNF only acts over very short distances however.

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26
Q

What does the atomic number tell you?

A

The number of protons in the nucleus, Z.

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27
Q

What is usually equal to the number of protons?

A

The number of electrons.

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28
Q

What determines the chemical properties of an element, and what element it is?

A

The number of electrons in the outer shell of an atom?

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29
Q

What does the atomic number of element determine?

A

The chemical identity of an element.

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30
Q

In the same element, does the atomic number differ or stay the same between every atom?

A

Stays the same.

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31
Q

What is the term for the number of nucleons?

A

The mass number, A.

32
Q

What is responsible for the majority of the mass of an atom?

A

The nucleons.

33
Q

How do you work out the mass number, A?

A

Number of protons + number of neutrons

34
Q

What are isotopes?

A

Atoms with the same number of protons but different number of neutrons.

35
Q

Do isotopes of the same element react differently or the same?

A

The same, because they have the same electronic configuration.

36
Q

Different isotopes of the same element can vary in which number? And why?

A

Mass number, due to the different number of neutrons in their nuclei.

37
Q

What did Neils Bohr propose in 1913?

A

He put forward the idea that the atom consisted of a tiny positive nucleus orbited by negatively - charged electrons. The electrons orbited in shells of fixed size and the movement of electrons from one shell to the next explained how atoms absorbed and gave out light. This is the beginning of what is called quantum theory.

38
Q

What did Erwin Schrodinger propose in 1926?

A

He worked out equation that used the idea that electrons had some of the properties of waves as well as those of particles. This led to the theory called quantum mechanics which can be used to predict the behaviour of sub-atomic particles.

39
Q

What did James Chadwick discover in 1932?

A

He discovered the neutron.

40
Q

What was the first thing Gilbert Lewis proposed?

A

The inertness of noble gases was related to them having a full outer shell of electrons.

41
Q

What was the second thing Gilbert Lewis proposed?

A

Ions were formed by losing or gaining electrons in order to attain full outer shells.

42
Q

What was the third thing Gilbert Lewis proposed?

A

Atoms could also bond by sharing electrons to form full outer shells.

43
Q

How any electrons can the first shell hold?

A

It can hold up to two electrons.

44
Q

How many electrons can the second shell hold?

A

It can hold up to eight electrons.

45
Q

How many electrons can the third shell hold?

A

It can hold up to eighteen electrons.

46
Q

What does a mass spectrometer determine?

A

Relative atomic masses, Ar. It determines the mass of separate atoms or molecules.

47
Q

What is the equation for relative atomic mass, Ar?

A

1/12 mass of 1 atom of Carbon 12

48
Q

What is the equation for relative molecular mass, Mr?

A

1/12 mass of 1 atom of Carbon 12

49
Q

What is the first stage of elelctrospray ionisation? What is the point of this step?

A

Vacuum - The whole apparatus is kept under a high vacuum to prevent the ions that are produced colliding with molecules.

50
Q

What is the second stage of electrospray ionisation? What is the point of this stage?

A

Ionisation - The sample to be investigated is dissolved in a volatile solvent and forced through a fine hollow hypodermic needle that is connected to the positive terminal of a high voltage supply. This produces tiny positively charged droplets which have lost electrons to the positive charge of the supply. The solvent evaporates from the droplets into the vacuum and the droplets get get smaller and smaller until until they contain no more than a positively charged ion.

51
Q

What is the third stage of electrospray/electron impact ionisation? What is the point of this stage?

A

Acceleration - The positive ions are attracted towards a negatively charged plate and accelerate towards it. Lighter ions and more highly charged ions achieve a higher speed.

52
Q

What is the fourth stage of electrospray/electron impact ionisation? What is the point of this stage?

A

Ion drift - The ions pass through a hole in the negatively charged plate, forming a beam and travel along a tube, called the flight tube, to a detector.

53
Q

What is the fifth stage of electrospray/electron impact ionisation? What is the point of this stage?

A

Detection - When ions with the same charge arrive at the detector, the lighter ones are first as they have higher velocities. The flight times are recorded. The positive ions pick up an electron from the detector, which causes a current to flow.

54
Q

What is the sixth stage of electrospray/electron impact ionisation? What is the point of this stage?

A

The signal from the detector is passed to a computer which generates a mass spectrum.

55
Q

What is the first of electron impact ionisation? What is the point of this stage?

A

A hot wire filament is used as an electron gun to fire electrons at the sample to them into ions.

56
Q

How do you work out the relative atomic mass from a mass spectrum?

A
                   Sum of abundance
57
Q

How are main energy levels labelled?

A

Just numbers.

58
Q

How are sub-levels labelled?

A

s, p, d & f.

59
Q

What do the shapes of orbitals represent?

A

They represent a volume of space in which there is a 95% probability of finding an electron and they influence the shapes of molecules

60
Q

What does the first main energy level consist of?

A

A single s-orbital.

61
Q

What does the second main energy level consist of?

A

A single s-orbital and three p-orbitals of slightly higher energy.

62
Q

What does the third main energy level consist of?

A

A single s-orbital, three p-orbitals of slightly higher energy, and five d-orbitals of slightly higher energy still.

63
Q

How many electrons can a single atomic orbital hold?

A

It can hold a maximum of two electrons.

64
Q

How many electrons can an s-orbital hold?

A

It can hold up to two electrons.

65
Q

How many electrons can a p-orbital hold?

A

p-orbitals can hold up to two electrons each, but always come in groups of three of the same energy, to give a total of up to six electrons in the p-sub-level.

66
Q

How many electrons can a d-orbital hold?

A

d-orbitals can hold up to two electrons each, but always come in groups of five of the same energy, to give a total of up to ten electrons in the d-sub-level.

67
Q

What must two electrons in the same orbital have?

A

Opposite spin.

68
Q

How is the property of spin represented?

A

Opposite arrows in a spin diagram.

69
Q

How are atomic orbitals filled? Why are they filled this way?

A

They are filled singularly before pairing starts. This is because the electrons repel each other.

70
Q

Why is the 4s sub-shell filled before the 3d sub-shell?

A

The 4s sub-shell is lower in energy than the 3d sub-shell.

71
Q

What is the definition of ionisation energy?

A

The energy required to remove a mole of electrons fro a mole of atoms in the gaseous state.

72
Q

What is ionisation energy measured in?

A

kJ mol^-1

73
Q

Why does the first electron need the least energy to remove?

A

Because it is being removed from a neutral atom.

74
Q

What is the increase of energy in ionisation energies called?

A

Successive ionisiation energies.

75
Q

What is the sequence for atomic orbitals?

A

1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 4d10, 4f14

76
Q

How does ionisation energy differ across a period?

A

Ionisation energies generally increase across a period because the nuclear charge and this makes it more difficult to remove the electron.

77
Q

How does the ionisation energy differ down a group?

A

Ionisation energies generally decrease down a group because the outer electron is in a main level that gets further from the nucleus in each case, and the further the outer electron is from the nucleus the weaker the electrostatic force of attraction between them and the effect of shielding becomes increasingly prominent.