Atomic Structure and the Periodic Table — Free IB MYP5 Chemistry Questions

Atomic Structure and the Periodic Table — Free MYP5 Chemistry Practice Questions

1QuestionGroup 17 Halogens and Group 18 Noble GasesConcept Practice

2 marks~3 minCriterion A

A test tube contains a colourless aqueous solution of potassium iodide (

KI

). A few drops of chlorine water are added. The solution turns orange-brown.

Identify the halogen produced in this reaction. [1]

Explain why chlorine is able to displace iodide ions from the potassium iodide solution. [1]

Solutions

2QuestionChemical Properties Based on PositionConcept Practice

2 marks~3 minCriterion A

The periodic table below shows a highlighted element at Group 2, Period 3.

Deduce the identity of the highlighted element. [1]

Explain one chemical property that can be inferred from its position in the periodic table. [1]

Solutions

3QuestionAtomic Number Mass Number and Nuclear SymbolConcept Practice

2 marks~3 minCriterion A

Carbon-14 is a radioactive isotope used in archaeological dating. Its nucleus contains 6 protons and 8 neutrons.

Deduce the mass number and atomic number of carbon-14. [1]

Construct the complete nuclear symbol for this atom, showing the mass number and atomic number in their correct positions relative to the element symbol. [1]

Solutions

4QuestionCalculating Relative Atomic Mass RAMConcept Practice

2 marks~3 minCriterion A

A mass spectrum of chlorine shows two peaks: one at

m/z = 35

with a relative abundance of 75.77% and one at

m/z = 37

with a relative abundance of 24.23%.

Deduce the identity of the isotope responsible for each peak, using correct isotopic notation. [1]

Using the data above, calculate the relative atomic mass (RAM) of chlorine. Give your answer to one decimal place. [1]

Solutions

5QuestionElectron Configuration NotationConcept Practice

2 marks~3 minCriterion A

A sodium atom (

\text{Na}

) has 11 protons and therefore 11 electrons. The shell model places electrons in successive shells outward from the nucleus: the first shell holds a maximum of 2 electrons, the second shell holds a maximum of 8 electrons, and any remaining electrons occupy the third shell.

State the number of electrons in each shell of a sodium atom. [1]

Deduce the complete electron configuration of sodium in the notation used for the shell model, showing shells in order from innermost to outermost. [1]

Solutions

6QuestionIdentifying Groups Periods and Atomic NumberAssessment Practice

5 marks~8 minCriterion C

A student investigated the reaction of Group 1 metals with water and recorded the following data.

Metal — Time for complete reaction (s) — Observations

Li	120	fizzes gently, moves slowly
Na	45	fizzes vigorously, moves rapidly
K	10	reacts explosively, flame produced

The student concluded: "Reactivity increases down Group 1 because the atomic radius decreases, so the outer electron is held more tightly and reacts more easily."

State the correct trend in atomic radius down Group 1. [1]

Explain, using atomic radius and electron shielding, why reactivity increases from Li to K. [2]

Evaluate the student's conclusion using the experimental data and your knowledge of periodic trends. [2]

Solutions

7QuestionGroup 17 Halogens and Group 18 Noble GasesAssessment Practice

7 marks~11 minCriterion D

A government is evaluating a potential ban on brominated flame retardants (BFRs) in electronics. BFRs reduce fire-related fatalities but persist in the environment, accumulate in food chains, and pose health risks to humans and wildlife. Two alternatives have been assessed:

Fire deaths prevented per 100,000 units: BFRs = 12, Alternative A (phosphorus-based) = 8, Alternative B (inorganic hydroxide) = 6

Environmental persistence (years): BFRs = 50, Alternative A = 5, Alternative B = 2

Annual cost (million dollars): BFRs = 1.5, Alternative A = 2.0, Alternative B = 2.5

Explain one chemical property of halogens that contributes to the environmental persistence of BFRs. [2]

Evaluate the trade-offs between fire safety, environmental impact, and annual cost for BFRs and both alternatives, using the data provided. [3]

Discuss one limitation of using this data alone to decide whether to ban BFRs. [2]

Solutions

8QuestionGroup 1 Alkali MetalsAssessment Practice

3 marks~5 minCriterion B

The bar chart below shows the time required to collect

50 \text{ cm}^3

of hydrogen gas when lithium (Li), sodium (Na), and potassium (K) each react separately with excess water.

Time to collect

50 \text{ cm}^3

\text{H}_2

:
Li: 120 s — Na: 45 s — K: 10 s

The reaction for each metal M is:

2\text{M} + 2\text{H}_2\text{O} \rightarrow 2\text{MOH} + \text{H}_2

State the trend in reaction rate shown by the data. [1]

Explain how atomic structure changes down Group 1 affect the ease of losing the outer electron. [1]

Analyse why potassium reacts significantly faster than lithium, using both the data and your understanding of electron loss. [1]

Solutions

9QuestionPredicting Properties of Unknown ElementsAssessment Practice

5 marks~8 minCriterion B

The table below shows atomic radius and first ionisation energy for Group 14 elements.

Element	C	Si	Ge	Sn	Pb	Fl
Atomic radius (pm)	77	111	125	145	175	?
First ionisation energy (kJ/mol)	1086	787	762	709	715	?

Flerovium (Fl, element 114) is a synthetic Group 14 element positioned below lead.

Explain the trend in atomic radius from C to Pb, and deduce the atomic radius of Fl. [2]

Explain the trend in first ionisation energy from C to Pb, and deduce the first ionisation energy of Fl. [2]

Construct a balanced chemical equation, with state symbols, for the reaction of Fl with oxygen. Justify the oxidation state you have assigned to Fl, referring to trends in Group 14. [1]

Solutions

10QuestionChemical Properties Based on PositionAssessment Practice

4 marks~6 minCriterion D

Chlorine (Period 3) and iodine (Period 5) are both Group 17 halogens used to disinfect water. Chlorine is widely used in municipal water treatment but reacts with organic matter to form trihalomethanes (THMs), which are potentially carcinogenic. Iodine is used in emergency purification tablets but is unsuitable for large-scale treatment. Prolonged iodine exposure can disrupt thyroid function.

State the periodic trend in reactivity down Group 17 and explain, in terms of atomic structure, why chlorine is more reactive than iodine. [1]

Using their positions in the periodic table, analyse one advantage and one disadvantage of each halogen for water disinfection. [2]

Evaluate the limitations of using periodic trends alone to assess the environmental and health safety of chlorine and iodine in water treatment. [1]

Solutions

11QuestionElectronegativity Across PeriodsAssessment Practice

8 marks~12 minCriterion C

Evaluate the societal and environmental trade-offs of replacing chlorine-based refrigerants (e.g., CFCs) with fluorine-containing compounds (e.g., HFCs), using your understanding of electronegativity trends. Your evaluation should include:

[2 marks] Explain how the high electronegativity of fluorine (4.0 on the Pauling scale) compared to chlorine (3.0) affects the strength of carbon-halogen bonds, and how this relates to ozone depletion potential.

[3 marks] Discuss one societal benefit and one environmental cost of the widespread adoption of HFCs, referencing the role of bond strength in each case.

[3 marks] Reflect on the limitations of using electronegativity values alone to predict the overall environmental impact of a chemical technology. Consider factors such as atmospheric lifetime and infrared absorption.

Solutions

12QuestionAtomic Number Mass Number and Nuclear SymbolAssessment Practice

3 marks~5 minCriterion B

The table below shows data for four elements.

Element	Carbon	Oxygen	Magnesium	Calcium
Atomic number	6	8	12	20
Mass number	12	16	24	40
Number of protons	6	8	12	20
Number of neutrons	6	8	12	20

State the relationship between atomic number and number of protons. [1]

Using the data, deduce the relationship between mass number, protons, and neutrons. Support your answer with two examples from the table. [1]

Explain why the mass number and atomic number are equal for none of these elements, yet the number of protons and neutrons happen to be equal for all four. [1]

Solutions

13QuestionAtomic Number Mass Number and Nuclear SymbolAssessment Practice

5 marks~8 minCriterion C

A mass spectrometer analysed pure samples of neon (Ne), magnesium (Mg), and chlorine (Cl). The isotopic data obtained are shown below.

Neon — m/z: 19.99 (90.48%), 20.99 (0.27%), 21.99 (9.25%)
Magnesium — m/z: 23.99 (78.99%), 24.99 (10.00%), 25.99 (11.01%)
Chlorine — m/z: 34.97 (75.78%), 36.97 (24.22%)

Accepted average atomic masses: Ne = 20.18, Mg = 24.31, Cl = 35.45.

Calculate the weighted average atomic mass for each element using the data above. Show all working. [3]

Deduce whether your calculated values are consistent with the accepted periodic table values, giving a quantitative comparison. [1]

Evaluate whether the neon mass spectrum is physically complete, given that the atomic number of neon is 10 and stable isotopes require a neutron-to-proton ratio close to 1 for light elements. [1]

Solutions

14QuestionAtomic Number Mass Number and Nuclear SymbolAssessment Practice

3 marks~5 minCriterion D

Technetium-99m (nuclear symbol:

^{99}_{43}\mathrm{Tc}

) is a radioisotope widely used in medical imaging. Its half-life is approximately 6 hours.

Deduce the number of protons and the number of neutrons in one atom of technetium-99m. [1]

Explain how the atomic number and mass number of technetium-99m together make it suitable for safe use as a medical imaging tracer. [1]

Evaluate one limitation of using radioactive isotopes with short half-lives in medical diagnostics. [1]

Solutions

15QuestionDefinition and Examples of IsotopesAssessment Practice

7 marks~11 minCriterion B

The table below shows isotopic data for three elements.

Hydrogen-1	1 proton	0 neutrons	stable
Hydrogen-2	1 proton	1 neutron	stable
Hydrogen-3	1 proton	2 neutrons	radioactive

Carbon-12	6 protons	6 neutrons	stable
Carbon-13	6 protons	7 neutrons	stable
Carbon-14	6 protons	8 neutrons	radioactive

Uranium-235	92 protons	143 neutrons	radioactive
Uranium-238	92 protons	146 neutrons	radioactive

Calculate the neutron-to-proton ratio for each isotope and identify the pattern linking this ratio to nuclear stability. [2]

Deduce a general rule, based on atomic number, that predicts whether an isotope is likely to be stable or radioactive from its neutron-to-proton ratio. [2]

Oxygen-16 has 8 protons and 8 neutrons; oxygen-18 has 8 protons and 10 neutrons. Oxygen-18 is in fact stable. Analyse whether your rule from (b) correctly predicts the stability of each isotope, and evaluate what this reveals about the limitations of a neutron-to-proton ratio rule. [3]

Solutions

16QuestionCalculating Relative Atomic Mass RAMAssessment Practice

5 marks~8 minCriterion D

A mass spectrometer analyses two iridium samples. The data are:

Sample A:

^{191}

Ir: 37.3% abundance;

^{193}

Ir: 62.7% abundance

Sample B:

^{191}

Ir: 62.7% abundance;

^{193}

Ir: 37.3% abundance

The standard atomic weight of iridium is 192.22.

Use the formula:

A_r = \frac{\sum(m_i \times a_i)}{100}

where

m_i

is the mass number and

a_i

is the percentage abundance.

Calculate

A_r

for both Sample A and Sample B, showing all working. [2]

Compare your calculated values to the standard atomic weight and deduce which sample is from a terrestrial source. [1]

Justify why the other sample is likely to be of meteoritic origin, referring to isotopic composition and nucleosynthetic processes. [2]

Solutions

17QuestionStability of Isotopes and Radioactivity IntroAssessment Practice

8 marks~12 minCriterion C

Four isotopes are listed below.

Isotope	C-12	C-14	U-238	Tc-99m
Protons	6	6	92	43
Neutrons	6	8	146	56
Neutron-to-proton ratio	1.00	1.33	1.59	1.30
Half-life	Stable	5730 years	4.5 billion years	6 hours
Decay mode	None	beta-minus	alpha	gamma

Consider the hypothesis: "All isotopes with more neutrons than protons are unstable."

Identify which isotopes in the table support the hypothesis and which contradict it. Justify your answer using data from the table. [3]

Explain how the band of stability accounts for the stability of C-12 and the instability of C-14. [2]

Evaluate whether the data in the table are sufficient to confirm the hypothesis. In your answer, refer to isotopes not shown in the table. [3]

Solutions

18QuestionElectron Configuration NotationAssessment Practice

6 marks~9 minCriterion B

Emission spectra data for four elements are shown below.

Element	H	He	Li	Be
Number of visible spectral lines	4	15	1	10
Electron configuration	$1s^1$	$1s^2$	$1s^2 2s^1$	$1s^2 2s^2$

Analyse the data to identify the relationship between the number of visible spectral lines and the number of valence electrons for these four elements. [2]

The emission spectrum of boron (B) shows 5 visible spectral lines. Deduce the full electron configuration of boron, using the pattern you identified in (a). [2]

Explain, with reference to the shell model of the atom, why more valence electrons in the same principal energy level do not always produce more visible spectral lines than elements in a lower principal energy level. [2]

Solutions

19QuestionRelating Configuration to ReactivityAssessment Practice

5 marks~8 minCriterion D

A water treatment plant disinfects drinking water using chlorine (Cl) gas. A chemist proposes switching to iodine (I) to reduce harmful by-products such as chlorinated hydrocarbons.

Electron configurations:
Cl: 2, 8, 7
I: 2, 8, 18, 18, 7

State the group and period of chlorine and iodine in the periodic table. [1]

Using their electron configurations, explain why iodine is less reactive than chlorine. [2]

Evaluate the proposal to replace chlorine with iodine for water disinfection, considering both the reduction in harmful by-products and the consequences of iodine's lower reactivity and excess iodine intake. [2]

Solutions

20QuestionElectronic Configuration of Ions IntroAssessment Practice

5 marks~8 minCriterion C

A student performs flame tests on four unknown metal compounds and records the following results:

Unknown X	Lilac, intensity 3
Unknown Y	Yellow-orange, intensity 8
Unknown Z	Brick red, intensity 4
Unknown W	Green, intensity 2

The student hypothesises: "Ions with a +2 charge always produce more intense flame colours than +1 ions."

Electron configurations of relevant metals:

\text{Na: } 1s^2 2s^2 2p^6 3s^1

(forms

\text{Na}^+

)

\text{K: } 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1

(forms

\text{K}^+

)

\text{Ca: } 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2

(forms

\text{Ca}^{2+}

)

Identify the metals most likely present in unknowns X, Y, and Z, and state the ion charge each metal forms. [2]

Using the electron configurations provided, explain why Na and K produce different flame colours despite both forming +1 ions. [1]

Evaluate whether the flame test data support or contradict the student's hypothesis, using specific intensity values in your answer. [2]

Solutions