Ib Chemistry Hl Topic 2

1. State the position of protons, neutrons and electrons in the atom.

P+N in nucleus. Electrons orbiting in electron cloud surrounding nucleus.

P+N orbiting around the nucleus. Electrons clustered in the nucleus.

P in nucleus, N orbiting in electron cloud. Electrons distributed in the nucleus.

P in electron cloud, N in nucleus. Electrons orbiting in nucleus.

2. State the relative masses and relative charges of protons, neutrons and electrons.

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Protons have a relative mass of 1 and a relative charge of -1. Neutrons have a relative mass of 0 and a relative charge of 0. Electrons have a relative mass of 1 and a relative charge of +1.

Protons have a relative mass of 1 and a relative charge of 0. Neutrons have a relative mass of 0 and no charge. Electrons have a relative mass of 0 and a relative charge of -1.

Protons have a relative mass of 0 and a relative charge of -1. Neutrons have a relative mass of 0 and no charge. Electrons have a relative mass of 1 and a relative charge of +1.

3. Define the terms mass number (A), atomic number (Z) and isotopes of an element.

Atomic number: ZY: The Z, represents the total number of electrons in the nucleus of an atom.

Mass Number: AX: the X, represents the total number of protons and neutrons in the nucleus of an atom.

Isotope: Atoms with the same number of protons and electrons but different numbers of neutrons.

Mass Number: AX : the A, represents the total number of protons and neutrons in the nucleus of anatom. Atomic number: ZX: The Z, represents the total number of protons in the nucleus of an atom.Isotope: Atoms with the same number of protons but different numbers of neutrons.

Mass number (A) represents protons and neutrons, atomic number (Z) represents protons only, and isotopes have same protons but different neutrons.

Explanation

Mass number (A) represents protons and neutrons, atomic number (Z) represents protons only, and isotopes have same protons but different neutrons.

4. Deduce the symbol for an isotope given its mass number and atomic number.

AZ X, for example, 16S

AZ X, for example, 14N

The following notation should be used: AZ X , for example, 12C

AZ X, for example, 8O

The correct notation for an isotope includes the mass number (A) and atomic number (Z) followed by the chemical symbol (X). For example, 12C represents the carbon isotope with 6 protons (atomic number) and 6 neutrons (mass number).

Explanation

The correct notation for an isotope includes the mass number (A) and atomic number (Z) followed by the chemical symbol (X). For example, 12C represents the carbon isotope with 6 protons (atomic number) and 6 neutrons (mass number).

5. Calculate the number of protons, neutrons and electrons in atoms and ions from the mass number, atomic number and charge.

For Helium: Atomic Number: 2, Mass Number: 4, Charge: +1

For Oxygen: Atomic Number: 8, Mass Number: 18, Charge: +2

For Lithium: Atomic Number: 3, Mass Number: 6, Charge: -1

For Hydrogen:
Atomic Number: 1Mass Number: 2Charge: Neutral

The correct answer for Hydrogen with atomic number 1, mass number 2, and being neutral serves as a reference point to calculate protons, neutrons, and electrons. The incorrect answers provided showcase different elements with varying atomic numbers, mass numbers, and charges to highlight the importance of correctly applying the formula to calculate the particles in atoms and ions.

Explanation

The correct answer for Hydrogen with atomic number 1, mass number 2, and being neutral serves as a reference point to calculate protons, neutrons, and electrons. The incorrect answers provided showcase different elements with varying atomic numbers, mass numbers, and charges to highlight the importance of correctly applying the formula to calculate the particles in atoms and ions.

6. Compare the properties of the isotopes of an element.

Similar chemical properties.Slightly different physical properties e.g. m.p, b.p, and density.

Completely different properties in all aspects.

Different chemical properties. Similar physical properties.

Isotopes of the same element do not exist.

7. Discuss the uses of radioisotopes.

Examples should include 14C in radiocarbon dating,60Co in radiotherapy, and 131I and 125I as medicaltracers.
Students should be aware of the dangers toliving things of radioisotopes but also justify theirusefulness with the examples above.

Radioisotopes are only used in military operations.

Radioisotopes have no impact on medical field or scientific research.

Radioisotopes are not used in any practical applications.

Radioisotopes have various important applications in fields such as medicine, agriculture, and scientific research. The examples provided in the correct answer illustrate how radioisotopes are utilized for radiocarbon dating, radiotherapy, and medical tracing purposes.

Explanation

Radioisotopes have various important applications in fields such as medicine, agriculture, and scientific research. The examples provided in the correct answer illustrate how radioisotopes are utilized for radiocarbon dating, radiotherapy, and medical tracing purposes.

8. Describe and explain the operation of a mass spectrometer.

Mass spectrometers operate by converting samples into liquid form before analysis.

A simple diagram of a single beam massspectrometer is required. The following stages
of operation should be considered: vaporization,ionization, acceleration, deflection and detection.
VIADD
Stages of Operation: Vaporization of sample, ionization to produce M+ ions, accelerationof ions by electric field, deflection of ions by magnetic field, vacuum, detection of ions.
Degree of deflection: Lower the mass, higher the deflection. Higher the charge, higher the deflection.

The acceleration stage in a mass spectrometer involves cooling the ions to increase their mass.

A mass spectrometer detects particles based on their color rather than mass and charge.

A mass spectrometer operates by vaporizing a sample, ionizing to produce ions, accelerating the ions, deflecting them by a magnetic field, and finally detecting them. The process does not involve converting samples into liquid form, cooling ions, or detecting based on color.

Explanation

A mass spectrometer operates by vaporizing a sample, ionizing to produce ions, accelerating the ions, deflecting them by a magnetic field, and finally detecting them. The process does not involve converting samples into liquid form, cooling ions, or detecting based on color.

9. Describe how the mass spectrometer may be used to determine relative atomic mass using the 12C scale.

It measures the volume of an atom to determine its mass.

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It counts the number of isotopes present in a sample to determine the atomic mass.

It analyzes the color of elements to calculate their atomic mass.

The mass spectrometer works by ionizing a sample and separating the ions based on their mass-to-charge ratio. By comparing the mass spectrum of an element to a standard such as 12C, the relative atomic mass can be determined.

Explanation

The mass spectrometer works by ionizing a sample and separating the ions based on their mass-to-charge ratio. By comparing the mass spectrum of an element to a standard such as 12C, the relative atomic mass can be determined.

10. Calculate non-integer relative atomic masses and abundance of isotopes from given data.

Straightforward.
Relative Atomic Mass = %*Mass + %*Mass

Complex.Formula involving complex mathematical operations.

Incorrect.Relative Atomic Mass = %/Mass + %*Mass.

Direct.Sum of atomic masses and abundances without multiplication.

In this question, the correct answer provides a straightforward formula for calculating non-integer relative atomic masses and abundance of isotopes from given data. The incorrect answers include options that suggest complexity, direct sum without multiplication, and incorrect mathematical operations, which do not align with the correct formula provided in the question.

Explanation

In this question, the correct answer provides a straightforward formula for calculating non-integer relative atomic masses and abundance of isotopes from given data. The incorrect answers include options that suggest complexity, direct sum without multiplication, and incorrect mathematical operations, which do not align with the correct formula provided in the question.

11. Describe the electromagnetic spectrum.

Students should be able to identify the ultraviolet,visible and infrared regions, and to describe thevariation in wavelength, frequency and energyacross the spectrum.

Students should only focus on visible light when describing the electromagnetic spectrum.

There is no variation in wavelength, frequency, or energy across the electromagnetic spectrum.

The electromagnetic spectrum consists only of radio waves and microwaves.

The correct answer provides a comprehensive description of the electromagnetic spectrum, including the different regions and the variations in wavelength, frequency, and energy. The incorrect answers either limit the spectrum to specific regions or provide inaccurate information about its characteristics.

Explanation

The correct answer provides a comprehensive description of the electromagnetic spectrum, including the different regions and the variations in wavelength, frequency, and energy. The incorrect answers either limit the spectrum to specific regions or provide inaccurate information about its characteristics.

12. Distinguish between a continuous spectrum and a line spectrum.

Continuous spectrum: A spectrum representing all the colours of the rainbow: ROYGBV, with nodistinction between colors. Line Spectrum: Also known as absorption spectrum, all wavelengths have been absorbed by an atom(or whatever) as the light has passed through, except a few and these are shown as lines on thespectrum.

Continuous spectrum: Represents sound waves. Line Spectrum: Represents light waves.

Continuous spectrum: A spectrum representing only one color. Line Spectrum: Represents a mix of colors with no clear pattern.

Continuous spectrum: Consists of only straight lines. Line Spectrum: Consists of curved lines.

A continuous spectrum contains all the colors of the rainbow without distinction, while a line spectrum shows specific wavelengths that have been absorbed by an atom or material.

Explanation

A continuous spectrum contains all the colors of the rainbow without distinction, while a line spectrum shows specific wavelengths that have been absorbed by an atom or material.

13. Explain how the lines in the emission spectrum of hydrogen are related to electron energy levels.

The lines in the emission spectrum of hydrogen are random and do not have any relation to electron energy levels.

Students should be able to draw an energy leveldiagram, show transitions between differentenergy levels and recognize that the lines in a linespectrum are directly related to these differences.An understanding of convergence is expected.Series should be considered in the ultraviolet,visible and infrared regions of the spectrum.Calculations, knowledge of quantum numbers andhistorical references will not be assessed.
Emission spectrum: Shows the wavelengths of the lines that have been emitted, will consist of acontinuous spectrum with a few lines blacked out. (that have been absorbed).
Movement between energy levels requires energy, energy differences correspond to spectral lines

The lines in the emission spectrum of hydrogen are caused by the interaction of hydrogen molecules with other elements present in the environment.

The emission spectrum of hydrogen is solely determined by the temperature of the environment in which it is observed.

Understanding the relationship between the emission spectrum lines and electron energy levels is essential in explaining the behavior of hydrogen atoms. The incorrect answers provided do not accurately address this relationship and may lead to misconceptions.

Explanation

Understanding the relationship between the emission spectrum lines and electron energy levels is essential in explaining the behavior of hydrogen atoms. The incorrect answers provided do not accurately address this relationship and may lead to misconceptions.