Atomic Structure Flashcards
1
Q
What are the three fundamental particles of an atom?
A
Protons, neutrons, electrons
These particles have relative charges and masses.
2
Q
What is the structure of an atom?
A
A nucleus containing protons and neutrons surrounded by electrons
The nucleus is at the center of the atom.
3
Q
Define first ionisation energy.
A
The energy required to remove the outermost electron from a neutral atom in the gaseous state
It provides insights into electron configurations.
4
Q
What is the significance of ionisation energies in Period 3 and Group 2 elements?
A
They provide evidence for electron configuration in sub-shells and shells
Trends in ionisation energies reveal information about atomic structure.
5
Q
How are elements classified in the Periodic Table?
A
As s, p, d, or f block according to their position, determined by proton number
This classification reflects the electron configuration.
6
Q
What trends are observed in the physical properties of Period 3 elements?
A
Trends in atomic radius, first ionisation energy, and melting point
These trends arise from the structure and bonding of the elements.
7
Q
What is mass number (A) and atomic number (Z)?
A
Mass number (A) is the total number of protons and neutrons; atomic number (Z) is the number of protons
These numbers help determine the number of fundamental particles in atoms.
8
Q
What are isotopes?
A
Atoms of the same element with different numbers of neutrons
Isotopes have the same atomic number but different mass numbers.
9
Q
What does a time of flight (TOF) mass spectrometer do?
A
It measures the mass-to-charge ratio of ions
The process includes ionisation, acceleration, ion drift, ion detection, and data analysis.
10
Q
What information can mass spectrometry provide?
A
Relative isotopic mass and relative abundance of isotopes
It can also identify elements and determine relative molecular mass.
11
Q
How can one calculate relative atomic mass from isotopic abundance?
A
By interpreting mass spectra and using weighted means
This calculation is limited to mononuclear ions.
12
Q
Fill in the blank: The _______ is the total number of protons and neutrons in an atom.
A
mass number
This is represented as ‘A’.
13
Q
True or False: The atomic number (Z) determines the number of neutrons in an atom.
A
False
The atomic number indicates the number of protons.
14
Q
What is the trend in first ionisation energies of elements down a group?
A
First ionisation energy decreases down a group
15
Q
What is the trend in first ionisation energies across a period?
A
There is a general increase in first ionisation energies across a period, with exceptions
16
Q
Which elements are exceptions in Period 3 for first ionisation energy?
A
Aluminium and Sulphur
17
Q
Which elements are exceptions in Period 2 for first ionisation energy?
A
Boron and Oxygen
18
Q
What is a mass spectrometer used for?
A
To analyze elements or compounds and determine relative atomic mass (Ar) or relative molecular mass (Mr)
19
Q
What two factors does a mass spectrometer measure?
A
- Relative abundance
- Mass/charge (m/z) ratio
20
Q
What are the four steps in time-of-flight mass spectrometry?
A
- Ionisation
- Acceleration
- Ion Drift
- Detection
21
Q
Fill in the blank: A mass spectrometer uses a _______ to create a vacuum for the analysis process.
A
Vacuum Pump
22
Q
True or False: The mass spectrometer can only determine the relative atomic mass of atoms.
A
False
23
Q
What are the two methods of ionisation in a mass spectrometer?
A
Electrospray Ionisation and Electron-Impact Ionisation
These methods are used to convert samples into ions for analysis.
24
Q
Describe the process of Electrospray Ionisation.
A
Sample is dissolved in a volatile solvent, injected through a needle at high voltage, and ionised by gaining a proton.
This method is commonly used for large biomolecules.
25
Describe the process of Electron-Impact Ionisation.
Sample is vapourised, high-energy electrons are fired at the sample from an electron gun, knocking off one electron from each particle.
## Footnote
This method is typically used for smaller molecules.
26
What is the relationship between kinetic energy and mass and velocity in a mass spectrometer?
Kinetic Energy = ½ x mass x (velocity)²
## Footnote
This equation shows how kinetic energy is dependent on both the mass of the ion and its velocity.
27
What is the formula for calculating time in a mass spectrometer?
Time (s) = distance (m) / velocity (m/s)
## Footnote
This formula is used to determine how long it takes ions to travel through the flight tube.
28
In a mass spectrometer, do all ions have the same kinetic energy?
Yes, all ions have the same kinetic energy once accelerated.
## Footnote
However, they travel at different velocities.
29
Fill in the blank: In Electrospray Ionisation, the sample is injected through a needle at _______.
high voltage.
## Footnote
This high voltage is necessary for the ionisation process.
30
True or False: In Electron-Impact Ionisation, ions are created by gaining electrons.
False.
## Footnote
Ions are created by knocking off electrons.
31
What model did Ernest Rutherford propose based on his experiments?
Planetary model
## Footnote
This model suggests that atoms have a small, dense nucleus surrounded by electrons in orbit.
32
What experiment did Rutherford conduct to support his model?
Fired alpha particles at a gold foil
## Footnote
This experiment revealed that most of the atom is empty space, as most alpha particles passed through the foil.
33
What conclusion did Rutherford draw from his gold foil experiment?
Atoms must have a small, positive nucleus
## Footnote
The deflection of some alpha particles indicated the presence of a concentrated positive charge.
34
What key evidence supports the arrangement of electrons in shells?
Measuring ionisation energies
## Footnote
Ionisation energy data helps determine how electrons are organized around the nucleus.
35
What are the key features of the Bohr model?
* Small positive nucleus
* Electrons surrounding nucleus in energy levels
## Footnote
The Bohr model improved on Rutherford's model by introducing quantized energy levels for electrons.
36
Define ionisation energy.
The amount of energy needed to remove an electron from an atom in the gaseous state
## Footnote
Ionisation energy is a crucial concept in understanding atomic structure and chemical reactivity.
37
Fill in the blank: The ionisation energy of potassium can be represented by the equation _______.
K(g) → K⁺(g) + e⁻
## Footnote
This equation shows the process of removing an electron from a potassium atom.
38
True or False: The plum pudding model proposed by Thomson suggested that electrons were embedded in a positively charged 'soup'.
True
## Footnote
Thomson's model was later replaced by Rutherford's planetary model after experimental evidence showed otherwise.
39
What is the reason that the 4s sub shell fills before the 3d sub shell?
4s sub level electrons are lower in energy than 3d electrons
## Footnote
Energy level diagrams indicate this filling order.
40
What are the three key exceptions to the normal routine regarding electron configurations in d-block elements?
1. Chromium
2. Copper
3. [third exception not provided]
## Footnote
These exceptions arise from stability preferences for full or half-full sub shells.
41
What is the expected electron configuration for Chromium (proton number 24)?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴
## Footnote
This configuration would not be the most stable due to the half-full d sub shell preference.
42
What is the correct electron configuration for Chromium considering its stability?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
## Footnote
Chromium prefers a half-full d sub shell for increased stability.
43
What is the expected electron configuration for Copper (proton number 29)?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁹
## Footnote
This configuration would not be the most stable due to the full d sub shell preference.
44
What is the correct electron configuration for Copper considering its stability?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰
## Footnote
Copper prefers a full d sub shell for maximum stability.
45
True or False: The 4s sub shell is filled after the 3d sub shell in d-block elements.
False
## Footnote
The 4s sub shell is filled before the 3d sub shell due to energy levels.
46
Fill in the blank: d-block elements are more stable when they have a full, or _______ sub shell.
exactly half full
## Footnote
This stability preference leads to exceptions in electron configurations.
47
What happens to electrons when an atom forms a positive ion?
Electrons are lost from the atom, specifically from the highest energy electrons in the electron configuration.
48
In d-block elements, from which subshell are electrons removed when forming positive ions?
Electrons are removed from the 4s subshell, not the 3d shell.
49
What is the electron configuration of a neutral Iron (Fe) atom?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
50
What is the electron configuration of the Fe²⁺ ion?
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶
51
What is the proton number of Iron (Fe)?
26
52
What is the electron configuration of a neutral Copper (Cu) atom?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰
53
What is the electron configuration of the Cu⁺ ion?
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰
54
Fill in the blank: In transition metals, the _______ subshell loses electrons first when forming positive ions.
4s
55
True or False: For transition metals, the 3d subshell loses electrons before the 4s subshell when forming positive ions.
False
56
What is the general rule for losing electrons in transition metals when forming positive ions?
The outermost subshell loses electrons first to form positive ions.
57
What should be remembered about the order of electron loss in transition metal ions?
4s electrons are lost first, then 3d electrons.
58
What is the first ionisation energy of Sodium (Na)?
1600 kJ/mol
59
What is the first ionisation energy of Magnesium (Mg)?
1400 kJ/mol
60
What is the first ionisation energy of Aluminium (Al)?
1200 kJ/mol
61
What is the first ionisation energy of Silicon (Si)?
1000 kJ/mol
62
What is the first ionisation energy of Sulfur (S)?
800 kJ/mol
63
What is the first ionisation energy of Chlorine (Cl)?
600 kJ/mol
64
What is the first ionisation energy of Argon (Ar)?
400 kJ/mol
65
What is the general trend of ionisation energy across Period 3?
General increase
66
Ionisation energy tends to stay the same for which element in Period 3?
Stays the same
67
What configuration is represented by '3p'?
P Configuration
68
What is the electron configuration of Magnesium?
1s² 2s² 2p⁶ 3s²
69
Fill in the blank: The first electron is removed from the _______ shell.
[valence]
70
True or False: Paired electrons in the same orbital have a higher ionisation energy.
False
71
What is the electron configuration of Aluminium?
1s² 2s² 2p⁶ 3s² 3p¹
72
What is the electron configuration of Silicon?
1s² 2s² 2p⁶ 3s² 3p²
73
What is the electron configuration of Sulfur?
1s² 2s² 2p⁶ 3s² 3p⁴
74
What is the electron configuration of Chlorine?
1s² 2s² 2p⁶ 3s² 3p⁵
75
What is the electron configuration of Argon?
1s² 2s² 2p⁶ 3s² 3p⁶
76
What is a mass spectrometer used for?
To analyze elements or compounds and determine relative atomic mass (Ar) or relative molecular mass (Mr)
## Footnote
The mass spectrometer measures the relative abundance and mass/charge ratio (m/z) of ions.
77
What two factors does a mass spectrometer measure?
Relative abundance and mass/charge ratio (m/z)
## Footnote
These factors are crucial for determining the composition of the sample.
78
What happens to an unknown mixture when injected into a mass spectrometer?
It is converted into positive ions and accelerated to high speed
## Footnote
This process allows the ions to be analyzed based on their mass and charge.
79
What is the first step inside a mass spectrometer after injection?
Acceleration
## Footnote
Positive ions are attracted to a negatively charged plate and accelerate towards it.
80
How does the acceleration of ions depend on their properties?
It depends on the mass to charge (m/z) ratio
## Footnote
High m/z ratio ions accelerate to lower speeds than low m/z ratio ions.
81
What occurs during the ion drift phase in a mass spectrometer?
Ions pass through a hole in the negatively charged plate and travel towards the detector
## Footnote
Ions drift apart due to differing speeds.
82
What is recorded when ions hit the detector in a mass spectrometer?
The time of flight
## Footnote
This time varies based on the velocity of each ion.
83
What does the signal generated by the detector represent?
The size of the current is proportional to the number of each type of ion
## Footnote
This data is used for further analysis of the sample.
84
Why is a vacuum maintained inside the mass spectrometer?
To prevent particles from colliding with air molecules
## Footnote
This ensures accurate measurements of the ions.
85
What are the two methods of ionisation used in mass spectrometry?
Electron impact and electrospray ionisation
## Footnote
Both methods result in the sample particles gaining a positive charge.
86
Fill in the blank: The kinetic energy of ions in a mass spectrometer is given by the formula KE = _____
1/2 mv^2
## Footnote
This formula relates the kinetic energy (KE) to mass (m) and velocity (v) of the ions.
87
What are the two ways a sample can be ionised in mass spectrometry?
Electron impact and electrospray ionisation
88
What is electron impact also known as?
Electron ionisation
89
How is the sample prepared for electron impact ionisation?
The sample is vaporised
90
What generates the high energy electrons in electron impact ionisation?
An electron gun
91
What is the function of the hot wire filament in the electron gun?
It emits electrons
92
What happens to particles when high energy electrons are fired at them?
One electron is knocked off, forming a 1+ ion
93
What is formed when a molecule is ionised in electron impact ionisation?
A molecular ion
94
Provide an example of a reaction that occurs during electron impact ionisation.
CH4(g) → CH4*(g) + e-
95
What often occurs to the molecular ion after it is formed?
It breaks down into smaller fragments
96
True or False: Fragmentation of molecular ions is included in the specification for mass spectrometry.
False
97
What method is used for electrospray ionisation?
A sample is dissolved in a volatile solvent and injected through a fine hypodermic needle to create a mist.
## Footnote
The needle is connected to a high-voltage power supply that ionizes the particles.
98
What happens to the particles during electrospray ionisation?
Particles gain a proton from the solvent, producing XH+ ions.
## Footnote
These ions have a single positive charge and a mass of Mr + 1.
99
What is the purpose of the negative plate in the electrospray ionisation method?
The negative plate attracts the positively charged ions, allowing them to be accelerated.
## Footnote
This process is crucial for mass spectrometry analysis.
100
What is a characteristic of the electrospray ionisation technique?
It is known as a 'soft' ionisation technique, minimizing fragmentation.
## Footnote
This is particularly useful for analyzing biological molecules like proteins.
101
What formula is used to calculate the relative atomic mass (Ar) of elements?
Ar = (Mass 1 x Abundance 1) + (Mass 2 x Abundance 2) + ... + (Mass n × Abundance n) / (Abundance 1 + Abundance 2 + ... + Abundance n).
## Footnote
This formula allows for the calculation of average atomic mass based on isotopic abundance.
102
What is the relative atomic mass of chlorine based on its mass spectrum data?
35.5
## Footnote
This value is derived from the contributions of its isotopes: 75% of m/z = 35 and 25% of m/z = 37.
103
How is the relative atomic mass of neon calculated from its mass spectrum?
Ar = (20 x 9) + (22 x 1) / (9 + 1) = 20.2
## Footnote
The m/z ratios for neon isotopes are 20 and 22, and their respective abundances are 9 and 1.
104
Fill in the blank: The relative atomic mass of chlorine is ______.
35.5
105
True or False: There are chlorine atoms with a mass number of 35.5.
False
## Footnote
The value of 35.5 is an average that accounts for the isotopic distribution, not an actual mass number.
106
What should you do when completing calculations for relative atomic mass?
Always check that your answer looks sensible.
## Footnote
For example, the calculated mass should be between the m/z values of the isotopes.
107
What is the mass number of Titanium (Ti)?
46
## Footnote
The mass number is the total number of protons and neutrons in the nucleus of an atom.
108
What is the value of the Avogadro constant?
6.022 × 10²³ mol⁻¹
## Footnote
This constant represents the number of particles (atoms, molecules, etc.) in one mole of a substance.
109
How do you calculate the mass of one atom of Titanium?
Divide the molar mass by the Avogadro constant
## Footnote
Molar mass of Ti is 46 g/mol.
110
Fill in the blank: One mole of Titanium atoms weighs ______ g/mol.
46
## Footnote
This is based on the atomic mass from the periodic table.
111
True or False: The mass of one mole of atoms has the units g/mol.
True
## Footnote
This is a standard unit for molar mass.
112
What is the mass of one Beryllium (Be) atom?
1.49 × 10⁻²³ g
## Footnote
This is calculated using the mass of one mole of Be and the Avogadro constant.
113
What is the mass of one mole of Beryllium atoms?
9.4 g/mol
## Footnote
This is the molar mass of Beryllium.
114
How many atoms are in one mole of a substance?
6.022 × 10²³
## Footnote
This is known as the Avogadro constant.
115
Calculate the mass, in kg, of one atom of Titanium if its molar mass is 46 g/mol.
7.639 × 10⁻²⁵ kg
## Footnote
This is found by dividing 46 g by Avogadro's number and converting grams to kilograms.
116
What is the formula to convert grams to kilograms?
mass (kg) = mass (g) / 1000
## Footnote
This is a standard conversion factor.
117
What is the significance of the mass from the periodic table?
It represents the mass of one mole of atoms
## Footnote
This is used for calculations involving moles and mass.
