Podcast
Questions and Answers
What is the primary function of the mass spectrometer?
What is the primary function of the mass spectrometer?
In isotopes, what remains constant among them?
In isotopes, what remains constant among them?
Which technique is NOT used for ionization in a mass spectrometer?
Which technique is NOT used for ionization in a mass spectrometer?
What is the correct relationship for calculating the number of neutrons in an atom?
What is the correct relationship for calculating the number of neutrons in an atom?
Signup and view all the answers
What happens during the electron impact ionization process?
What happens during the electron impact ionization process?
Signup and view all the answers
What primarily causes the increase in first ionisation energy across a period?
What primarily causes the increase in first ionisation energy across a period?
Signup and view all the answers
Why does sodium (Na) have a lower first ionisation energy than neon (Ne)?
Why does sodium (Na) have a lower first ionisation energy than neon (Ne)?
Signup and view all the answers
Which characteristic is true for heavier ions in a mass spectrometer?
Which characteristic is true for heavier ions in a mass spectrometer?
Signup and view all the answers
What accounts for the small drop in first ionisation energy from magnesium (Mg) to aluminium (Al)?
What accounts for the small drop in first ionisation energy from magnesium (Mg) to aluminium (Al)?
Signup and view all the answers
What is a defining feature of electro spray ionization?
What is a defining feature of electro spray ionization?
Signup and view all the answers
What is the reason for the drop from phosphorus (P) to sulfur (S) in first ionisation energy?
What is the reason for the drop from phosphorus (P) to sulfur (S) in first ionisation energy?
Signup and view all the answers
In an atom of Lithium (Li), what is the mass number?
In an atom of Lithium (Li), what is the mass number?
Signup and view all the answers
Which of the following accurately describes the trend in second ionisation energy across periods?
Which of the following accurately describes the trend in second ionisation energy across periods?
Signup and view all the answers
What is unique about lithium's second ionisation energy compared to helium's?
What is unique about lithium's second ionisation energy compared to helium's?
Signup and view all the answers
Which factor does NOT contribute to the trend of ionisation energy across a period?
Which factor does NOT contribute to the trend of ionisation energy across a period?
Signup and view all the answers
What is meant by periodicity in the context of ionisation energy?
What is meant by periodicity in the context of ionisation energy?
Signup and view all the answers
What effect does increasing the mass of a particle have on its velocity, given constant kinetic energy?
What effect does increasing the mass of a particle have on its velocity, given constant kinetic energy?
Signup and view all the answers
How is the time of flight for an ion in a mass spectrometer determined?
How is the time of flight for an ion in a mass spectrometer determined?
Signup and view all the answers
What is the relationship between the size of the current generated by ions at the detector and their abundance?
What is the relationship between the size of the current generated by ions at the detector and their abundance?
Signup and view all the answers
When calculating relative atomic mass, what factors must be included in the equation?
When calculating relative atomic mass, what factors must be included in the equation?
Signup and view all the answers
What happens during electron impact ionization in a mass spectrometer?
What happens during electron impact ionization in a mass spectrometer?
Signup and view all the answers
When using electro spray ionization in a mass spectrometer, what is observed?
When using electro spray ionization in a mass spectrometer, what is observed?
Signup and view all the answers
What is the m/z value for a 2+ ion of 24Mg?
What is the m/z value for a 2+ ion of 24Mg?
Signup and view all the answers
How do mass spectrometers assist in identifying elements on other planets?
How do mass spectrometers assist in identifying elements on other planets?
Signup and view all the answers
What is the significance of the molecular ion peak in mass spectrometry?
What is the significance of the molecular ion peak in mass spectrometry?
Signup and view all the answers
In the calculation of relative atomic mass, what needs to be done when using relative abundance instead of percentage abundance?
In the calculation of relative atomic mass, what needs to be done when using relative abundance instead of percentage abundance?
Signup and view all the answers
During the mass spectrum analysis of Cl2, which isotopes are involved?
During the mass spectrum analysis of Cl2, which isotopes are involved?
Signup and view all the answers
What assumption can be made about ions with smaller m/z values in a flight tube?
What assumption can be made about ions with smaller m/z values in a flight tube?
Signup and view all the answers
What is a key feature of the Bohr model of the atom?
What is a key feature of the Bohr model of the atom?
Signup and view all the answers
Which combination of isotopes would yield an average atomic mass of approximately 63.5 for copper?
Which combination of isotopes would yield an average atomic mass of approximately 63.5 for copper?
Signup and view all the answers
Which of the following correctly describes the filling order of sublevels in an atom?
Which of the following correctly describes the filling order of sublevels in an atom?
Signup and view all the answers
What is the electronic configuration of a calcium atom?
What is the electronic configuration of a calcium atom?
Signup and view all the answers
Which subshell is filled first for d-block elements when they form ions?
Which subshell is filled first for d-block elements when they form ions?
Signup and view all the answers
What is the correct definition of first ionisation energy?
What is the correct definition of first ionisation energy?
Signup and view all the answers
Which factor does NOT affect the first ionisation energy?
Which factor does NOT affect the first ionisation energy?
Signup and view all the answers
Which statement is true regarding successive ionisation energies?
Which statement is true regarding successive ionisation energies?
Signup and view all the answers
What electronic structure corresponds to the ion Mg2+?
What electronic structure corresponds to the ion Mg2+?
Signup and view all the answers
Why does helium have a higher first ionisation energy than hydrogen?
Why does helium have a higher first ionisation energy than hydrogen?
Signup and view all the answers
Which of the following ions has a configuration of [Ar] 4s03d10?
Which of the following ions has a configuration of [Ar] 4s03d10?
Signup and view all the answers
In which group of the periodic table is an element with a large jump between its 2nd and 3rd ionisation energies likely to be found?
In which group of the periodic table is an element with a large jump between its 2nd and 3rd ionisation energies likely to be found?
Signup and view all the answers
Which element displays an electronic configuration of 1s22s22p63s23p6 4s13d5?
Which element displays an electronic configuration of 1s22s22p63s23p6 4s13d5?
Signup and view all the answers
What is the ionisation energy trend as you move down a group in the periodic table?
What is the ionisation energy trend as you move down a group in the periodic table?
Signup and view all the answers
When filling orbitals within the same sublevel, according to Hund's rule, how should electrons be placed?
When filling orbitals within the same sublevel, according to Hund's rule, how should electrons be placed?
Signup and view all the answers
What shape do p sublevels have?
What shape do p sublevels have?
Signup and view all the answers
What is the electronic configuration of an oxygen ion (O2-)?
What is the electronic configuration of an oxygen ion (O2-)?
Signup and view all the answers
Study Notes
Atomic Structure
-
Subatomic Particles: Atoms have three fundamental particles:
- Protons: Located in the nucleus, with a relative mass of 1 and a relative charge of +1.
- Neutrons: Located in the nucleus, with a relative mass of 1 and a relative charge of 0.
- Electrons: Located in orbitals, with a relative mass of 1/1840 and a relative charge of -1.
Atomic Representation
-
Lithium (Li) Example: The representation
⁷Li₃shows:- Atomic number (Z): 3 (number of protons).
- Mass number (A): 7 (total number of protons and neutrons).
- Number of neutrons: Calculated as A - Z = 7 - 3 = 4
Isotopes
- Definition: Atoms of the same element with the same number of protons but different numbers of neutrons are called isotopes.
- Chemical properties: Isotopes have similar chemical properties due to the same electronic structure.
- Physical properties: Isotopes may have slightly differing physical properties due to their varying masses.
Mass Spectrometry
-
Purpose: Used to identify and quantify isotopes in a sample.
-
Conditions: Must be under vacuum to avoid interference from air particles.
-
Steps:
- Ionisation: Sample is converted into ions (e.g., electron impact, electrospray ionisation). Electron impact is best for smaller molecules, while electrospray is preferred for larger organic molecules.
-
Acceleration: Positive ions are accelerated to a constant kinetic energy by an electric field.
- Lighter ions accelerate faster.
- Heavier ions accelerate slower.
- Flight Tube: Ions travel through a tube where their flight time differs based on mass-to-charge ratio (m/z). Lighter ions move faster.
- Detection: Ions reach a detector generating a current proportional to abundance.
-
Time of Flight (TOF) Calculations: Time taken for an ion to travel through the flight tube depends on its velocity and the length of the tube. The velocity in turn depends on the ion's mass, ensuring that heavier ions take longer to travel.
- The mass-to-charge ratio (m/z) is determined for each isotope.
- Relative atomic mass(RAM) calculation is based on the percentage abundance of isotopes.
Calculating Relative Atomic Mass (RAM)
- Formula: RAM = ∑ (isotopic mass × % abundance) / 100
- Variations: can be used if relative abundance is used instead of percentage abundance.
- Examples of calculations provided.
Mass Spectra for Diatomic Molecules
- Diatomic molecules: Examples for Cl₂and Br₂show that peaks are created due to different isotope combinations.
Electronic Structure
-
Models: Early Bohr models, modern models consider principal energy levels(numbered 1,2,3..),
- sub-energy levels labeled s , p, d, and f
- s holds up to 2 electrons
- p holds up to 6 electrons
- d holds up to 10 electrons
- f holds up to 14 electron
- Filling Order: Electrons fill orbitals in order of increasing energy. (Example 3d is higher in energy than 4s) Specific filling order: 1s → 2s →2p → 3s → 3p → 4s → 3d → 4p and so on.)
- Orbital Shapes: s orbitals are spherical, p orbitals are dumbbell-shaped, etc.
-
Electronic Configuration: Writing electronic arrangements using numbers and letters.
- Example for oxygen: 1s²2s²2p⁴
Electronic Structure of Ions
- Positive Ions: Electrons are lost from the outermost shell.
- Negative Ions: Electrons are gained.
Ionization Energies
-
Definition: First ionization energy is the energy required to remove one mole of electrons from one mole of gaseous atoms.
-
Factors: Affecting ionization energy include:
- Nuclear attraction: Stronger with more protons.
- Electron distance: Greater distance, weaker attraction.
- Shielding: Inner electrons repel outer electrons, reducing attraction.
-
Successive Ionization Energies: Energies required to remove successive electrons increase due to increased nuclear attraction on remaining electrons.
-
Patterns: -Increases across a period due to increasing nuclear attraction. -Decreases down a group due to increasing distance from the nucleus and shielding. -Specific drops in the graph, due to additional influencing factors, are explained in detail.
-
Groups 1 and 2: These patterns in successive ionization energies give information about the element's electronic structure.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on atomic structure, including subatomic particles, atomic representation, and isotopes. Understand the differences between protons, neutrons, and electrons, and explore how isotopes affect chemical and physical properties.
