Author: Cheryl Turner

IB Chemistry – HL 
Topic 2 Questions 
1.	What is the electron configuration for an atom with Z = 22?
A.	1s^22s^22p^63s^23p^63d^4
B.	1s^22s^22p^63s^23p^64s^24p^2
C.	1s^22s^22p^63s^23p^63d^24p^2
D.	1s^22s^22p^63s^23p^64s^23d^2
(Total 1 mark)
2.	What is the total number of p orbitals containing one or more electrons in germanium (atomic number 32)?
A.	2
B.	3
C.	5
D.	8
(Total 1 mark)
3.	How many electrons are there in all the d orbitals in an atom of xenon?
A.	10
B.	18
C.	20
D.	36
(Total 1 mark)
4.	Which is correct about the element tin (Sn) (Z = 50)?

Number of main energy levels containing electrons

Number of electrons in
highest main energy level

A. | 4 | 4
B. | 4 | 14
C. | 5 | 4
D. | 5 | 14
(Total 1 mark)

5.	What is the total number of electrons in p orbitals in an atom of iodine?
A.	5
B.	7
C.	17
D.	23
(Total 1 mark)
6.	A transition metal ion X^2+ has the electronic configuration [Ar]3d^9. What is the atomic number of the element?
A.	27
B.	28
C.	29
D.	30
(Total 1 mark)
7.	How many orbitals are there in the n = 3 level of an atom?
A.	3
B.	5
C.	7
D.	9
(Total 1 mark)
8.	What is the electron configuration for the copper(I) ion, (Z = 29)?
A.	[Ar]4s^23d^9
B.	[Ar]4s^13d^10
C.	[Ar]4s^13d^9
D.	[Ar]3d^10
(Total 1 mark)
9.	(i)	State the full electron configuration for argon.
……………………………………………………………………………………………
(1)
(ii)	Give the formulas of two oppositely charged ions which have the same electron configuration as argon.
……………………………………………………………………………………………
(2)
(Total 3 marks)

10.	(a)	Use the Aufbau principle to write the electron configuration of an atom of germanium.
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(1)
(b)	The successive ionization energies of germanium are shown in the following table:
1^st | 2nd | 3rd | 4th | 5^th

Ionization energy /
kJ mol^–1

760

1540

3300

4390

8950

(i)	Identify the sub-level from which the electron is removed when the first ionization energy of germanium is measured.
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(1)
(ii)	Write an equation, including state symbols, for the process occurring when measuring the second ionization energy of germanium.
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(1)
(iii)	Explain why the difference between the 4th and 5th ionization energies is much greater than the difference between any two other successive values.
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(2)
(Total 5 marks)
11.	(i)	Explain why successive ionization energies of an element increase.
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(1)
(ii)	Explain how successive ionization energies account for the existence of three main energy levels in the sodium atom.
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(3)
(Total 4 marks)
IB Chemistry – HL 
Topic 2 Answers
1.	D
[1]
2.	D
[1]
3.	C
[1]
4.	C
[1]
5.	D
[1]
6.	C
[1]
7.	D
[1]
8.	D
[1]
9.	(i)	1s^22s^22p^63s^23p^6;	1
Do not accept [Ne] 3s^23p^6  or  2, 8, 8.
(ii)	K^+ /Ca^2+ /Sc^3+/Ti^4+;
Cl^–/S^2–/P^3–;	2
Accept other suitable pairs of ions.
[3]
10.	(a)	1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^2/[Ar] 4s^2 3d^10 4p^2;	1
Do not penalize for interchanging 4s^2and 3d^10.
(b)	(i)	(4)p;	1
(ii)	Ge^+(g) ® Ge^2+(g) + e^-;	1
Do not penalize for e^-(g).
Accept loss of electron on LHS.
(iii)	5th electron removed from energy level closer to nucleus/5th electron
removed from 3rd energy level and 4th electron from 4th energy
level/OWTTE;
	attraction by nucleus or protons greater (for electrons closer to
nucleus)/OWTTE;	2
[5]
11.	(i)	same nuclear charge, fewer electrons (thus more energy required to
remove successive electrons)/harder to remove an electron from
an ion with increasing positive charge/nucleus has greater effect
on smaller number of electrons/OWTTE;	1
(ii)	large increases in IE when 2nd and 10th electron removed; thus,
1st electron further from nucleus than 2nd electron; and 9th electron
further from nucleus than 10th electron; large increases indicate
changes in main energy levels/OWTTE;
OR
	outermost/3p electron has low IE because it is far/furthest from the nucleus;
	electron(s) in second shell/2p electrons are much closer (to nucleus) and
need much more energy to remove/IE much higher/very high/there is a
big jump in IE;
	electron(s) in first/innermost shell/1s electrons are even closer (to nucleus)
and need much more energy to remove (than those in second shell/2s or 2p
electrons);	3
[4]