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IBChemistry: HLDPExam Questions12. Atomic Structure (HL only)12.1 Electrons in Atoms

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First teaching 2014

Last exams 2024

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Electrons in Atoms (DP IB Chemistry: HL)

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12.1 Electrons in Atoms

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12.1 Electrons in Atoms

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1a1 mark

An element Y has the following first six ionisation energies in kJ mol-1. These are shown in the table below.

 

1st 

2nd

3rd

4th

5th

6th

Ionisation energy (kJ mol-1)

577

1820

2740

11600

14800

18400

State what group of the Periodic Table this element belongs to.

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1b1 mark

State what can be determined from the frequency of the convergence limit in a hydrogen emission spectrum.

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1c
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Hydrogen spectral data give the frequency of 3.30 x 1015  Hz for its convergence limit.

Calculate the ionisation energy, in J, for a single atom of hydrogen using Sections 1 and 2 of the Data Booklet.

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1d
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Calculate the wavelength, in m, for the electron transition corresponding to the frequency in part (c) using Section 1 of the Data Booklet.

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2a1 mark
State which element in Period 2 will have the highest first ionisation energy value.

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2b1 mark

Write an equation, including state symbols, for the third ionisation energy of beryllium.

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2c1 mark

The successive ionisation energies of an element, X, are shown below.

tdJL_HNg_successive-ionisation-energies
 

State how many shells element X has.

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2d1 mark

Deduce which group element X is in.

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3a1 mark

State the general trend in first ionisation energies across Period 3.

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3b2 marks

The first ionisation energy of aluminium is lower than magnesium. Write the full electron configurations of aluminium and magnesium.

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3c2 marks

Using the electron configurations from part (b), explain why the first ionisation energy of aluminium is lower than magnesium.

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3d1 mark

Write the equation, including state symbols, for the second ionisation energy of aluminium.

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1a2 marks
a)
The successive ionisation energies of an element, X, are shown below. The vertical axis plots log (ionisation energy) instead of ionisation energy to represent the data without an unreasonably long vertical axis.

q1_12-1_electrons-in-atoms-sq-medium_ib_hl

Identify element X and give its full electron configuration.

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1b3 marks
b)
Explain how the successive ionisation energy data for the element X are related to its electron configuration.

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1c2 marks
c)
Explain why the first ionisation energy of aluminium is lower than the first ionisation energy of magnesium.

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1d2 marks
d)
Explain why the first ionisation energy of sulfur is lower than the first ionisation energy of phosphorus.

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2a2 marks
a)
The successive ionisation energies of vanadium are shown.

q2a_12-1_electrons-in-atoms-sq-medium_ib_hl

State the sub-levels from which each of the first four electrons are lost

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2b2 marks
b)
Outline why there is an increase in ionisation energy from electron 3 to electron 5.

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2c3 marks
c)
Explain why there is a large increase in the ionisation energy between electrons 5 and 6.

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2d2 marks
d)
The first six ionisation energies, in kJ mol-1, of an element are shown below
   

IE1

IE2

IE3

IE4

IE5

IE6

578

1816

2744

11576

14829

18375

 

Explain the large increase in ionisation energy from IE3 to IE4

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3a2 marks
a)
Emission spectra provide experimental evidence for the existence of atomic energy levels.

i)
Explain the convergence of lines in a hydrogen emission spectrum.

ii)
State what can be determined from the frequency of the convergence limit.

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3b2 marks
b)
Determine the energy, in J, of a photon of red light, correct to two significant figures, given that the wavelength is 650.0 nm using Sections 1 and 2 of the Data Booklet.

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3c3 marks
c)
Calculate the first ionisation energy, in kJ begin mathsize 16px style mol to the power of negative 1 end exponent end style, for hydrogen given that its shortest wavelength in the Lyman series is 91.16 nm using Sections 1 and 2 of the Data Booklet.

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3d3 marks
d)
Describe why the energy required to reach the convergence limit on an emission spectrum is considered the ionisation energy for an atom. You should refer to the appearance of the spectrum, frequency, and energy in your answer.

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4a3 marks
a)

The first ionisation energies of the elements in period 3 are shown below.

q4a_12-1_electrons-in-atoms-sq-medium_hb_hl

Explain the general trend seen in ionisation energy across period 3.

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4b2 marks
b)

On the diagram below, sketch the line for the first ionisation energies of period 2 elements

q4b_12-1_electrons-in-atoms-sq-medium_ib_hl

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4c5 marks
c)
Sketch a graph of ionisation energy versus the number of electrons removed for five ionisations of silicon. Explain the shape of the trend you have drawn.
q4c_12-1_electrons-in-atoms_ib_hl-medium

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4d2 marks
d)
The wavelength of a line in the Balmer series of hydrogen is 726.2 m. Calculate the energy of photons emitted, in kJ, using Sections 1 and 2 of the Data Booklet.

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5a2 marks
a)
The first ionisation energies of the elements in period 3 are shown.

q5a_12-1_electrons-in-atoms-sq-medium_ib_hl

Draw a graph on the diagram to to show the second ionisation energies of the period 3 elements

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5b3 marks
b)
Explain the differences seen in first and second ionisation energies of the elements in period 3.

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5c2 marks
c)

Hydrogen spectral data give the frequency of 3.28 x 1015  s-1 for its convergence limit.

i)
Calculate the ionisation energy, in J, for a single atom of hydrogen using Sections 1 and 2 of the Data Booklet.

ii)
Calculate the wavelength, in nm, for the electron transition corresponding to the frequency in part (i) using Section 1 of the Data Booklet.

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5d2 marks
d)
On the diagram below, draw a line that corresponds to the first ionisation energy of hydrogen and explain your reasoning.

q5d_12-1_electrons-in-atoms-sq-medium_ib_hl

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1a4 marks

Successive ionisation energies provide evidence for the arrangement of electrons in atoms. In the table below the successive ionisation energies of oxygen are given.

Ionisation number

1

2

3

4

5

6

7

8

Ionisation energy (kJ mol-1)

1314

3388

5301

7469

10989

13327

71337

84080

i)
Give the equation, including state symbols for the third ionisation energy of oxygen. 

[2]

ii)
Explain how this data shows evidence of two energy shells in oxygen.

[2]

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1b3 marks

Amorphous(unorganized solid form) boron is used as a rocket fuel igniter and in pyrotechnic flares.

i)
Write an equation, including state symbols to show the process that occurs for first ionisation of boron, B. 

[1]

ii)
Suggest why the ionisation energy of boron is lower than that of beryllium going against the general trend in ionisation energies across the period.

[2]

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1c
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Using the table in part (a) and sections 1 and 2 of the data booklet, calculate the wavelength, in nm, of the convergence limit in the spectral lines of an oxygen atom.

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2a2 marks

Aluminium has 13 successive ionisation energies.

On the figure below, add crosses to show the 13 successive ionisation energies of aluminium. The value for the first ionisation energy is already completed.

You do not have to join the crosses.

St2ZbkBb_successive-ionisation-graph

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2b1 mark

This question is about ionisation energies of an element, X.

The figure below represents the log of the first ten successive ionisation energies of X plotted against the number of electrons removed.

ionisation-graphState the group of the periodic table where element X is found.

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2c4 marks

Element A has the following first six ionisation energies in kJ mol-1.

577, 1820, 2740, 11 600, 14 800, 18 400

i)
Explain how you know that element A is in group 3 of the periodic table.

[1]

ii)
Two elements B and C are in the same period as A, but B is in the group before A and C is in the group after A in the periodic table.
Give approximate first ionisation energies for elements B and C.

[1]

iii)
Explain, using ideas of electronic structure, the difference in ionisation energy values of element A compared to elements B and C.

[2]

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3a4 marks

The first ionisation energies of the elements H to K are shown below in the figure below

first-ionisation-energy-graph

State and explain the trend in first ionisation energies shown by the elements with the atomic numbers 2, 10 and 18

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3b1 mark

Compound J reacts with chlorine. The first five successive ionisation energies for an element J, are shown in the table below.

Energy number

1st

2nd

3rd

4th

5th

Ionisation energy value / kJ mol−1 

738

1450

7733

10543

13630


State the formula of the compound when element J reacts with chlorine.

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3c2 marks

The figure below shows the successive ionisation energies for a period 2 element.

graph2

With reference to electronic structures, state the identity of this element and explain your answer.

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4a5 marks

Electrons in atoms occupy orbitals. The figure below shows the first ionisation energies for six consecutive elements labelled A–F in kJ mol-1. 

ionisation-graph-2

i)
Complete the graph of the first ionisation energies for the next five elements.
[3]
ii)
Explain why the value of the first ionisation energy for D is greater than for C.

[2]

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4b4 marks

The sequence of the first three elements in the Periodic Table is hydrogen, helium and then lithium.

Explain why the first ionisation energy of hydrogen is less than that of helium but greater than that of lithium.

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4c
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Using the figure in part (a) and sections 1 and 2 of the data booklet, calculate the frequency, in THz, of the convergence limit of a single atom of element C.

The prefix Tera, T, corresponds to a power of 1012.

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5a3 marks

The table below shows the successive ionisation energies of an unknown element, X. 

Ionisation number

Ionisation energy / kJ mol-1

1st

578

2nd

1817

3rd

2745

4th

11577

5th

14842

6th

18379

Deduce the group number and identity of element X and explain your answer with reference to its electron configuration.

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5b3 marks

First ionisation energies decrease down groups in the Periodic Table.

Explain this trend and the effect on the reactivity of groups containing metals.

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5c4 marks

The ionisation energy values show a general increase across period 4 from gallium to krypton.

i)
State and explain how selenium deviates from this trend. 
[3]
ii)
Give one other element from period 2 or 3 which also deviates from this general trend, similar to selenium.
[1]

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