Using the Aufbau Principle and Hund’s rule, deduce which element below has the greatest number of unpaired electrons in its ground state.
Z = 13
Z = 14
Z = 15
Z = 16
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Syllabus Edition
First teaching 2023
First exams 2025
Using the Aufbau Principle and Hund’s rule, deduce which element below has the greatest number of unpaired electrons in its ground state.
Z = 13
Z = 14
Z = 15
Z = 16
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Which electron transition would emit radiation of the longest wavelength?
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Why is the second ionisation energy of magnesium higher than the first ionisation energy?
Less shielding
Ionic radius increases
Nuclear charge is increasing
Greater attraction between positive nucleus and outer electron
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Which is true about the emission spectrum of hydrogen in the visible region?
The lines converge at longer wavelengths
The lines converge at higher frequency
The lines come from transitions between n=∞ and n=1
The lines are regularly spaced
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The frequency of the point of convergence on a hydrogen emission spectrum is 32.883 x 1014 s-1.
What is the ionisation energy for one atom of hydrogen?
(h = 6.63 x 10-34 J s)
2.18 x 10-18 J
2.02 x 10-49 J
J
4.96 x 1045 J
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The first five ionisation energies of an element are shown below.
What element could this ionisation energy graph belong to?
N
P
Al
Na
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Which are correct explanation(s) for the increase in ionisation energy across a period?
I. Nuclear charge increases
II. Atomic radius decreases
III. Shielding remains constant
I and II only
I and III only
I and III only
I,II and III
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Which spectrum belongs to hydrogen?
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There are six unpaired electrons in atoms of element Z. What could element Z be?
sulfur
iron
carbon
chromium
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The diagram shows three orbitals labelled 1, 2 and 3.
What is the correct label for each orbital?
px, py and pz
s, pz and py
s, px and pz
s, px and py
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What is the electronic configuration of an ion with a single negative charge and atomic number 17?
1s2 2s2 2p6 3s1 3p6
1s2 2s2 2p6 3s2 3p6
1s2 2s2 2p6 3s1 3p5
1s2 2s2 2p6 3s2 3p5
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What is the correct sequence for the orbitals shown in an atom of vanadium in order of decreasing energy?
3s 3p 4s 3d
4s 3d 3s 3p
4s 3d 3p 3s
3d 4s 3p 3s
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The second ionisation energy of magnesium is 1451 kJ mol-1.
Which equation correctly represents this statement?
Mg+(g) → Mg2+(g) + e- ΔHӨ = -1451 kJ mol-1
Mg+(g) → Mg2+(g) + e- ΔHӨ = +1451 kJ mol-1
Mg(g) → Mg2+(g) + 2e- ΔHӨ = +1451 kJ mol-1
Mg(g) → Mg+(g) + e- ΔHӨ = -1451 kJ mol-1
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X, Y and Z are consecutive elements in the third Period of the Periodic Table. Element Y has the highest first ionisation energy and also the lowest melting point of these three elements.
What could be the identities of X, Y and Z?
silicon, phosphorus, sulfur
sodium, magnesium, aluminium
aluminium, silicon, phosphorus
magnesium, aluminium, silicon
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An element in the d block of the periodic table forms a +4 ion and has the electron configuration of [Ar] 3d1.
What is the identity of the element?
Chromium
Copper
Vanadium
Silicon
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Deduce the correct information about the element tin, Sn (Z = 50)
Number of occupied main energy levels |
Number of electrons in the highest main energy level |
|
A |
4 |
4 |
B |
4 |
14 |
C |
5 |
4 |
D |
5 |
14 |
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Which of the following calculations gives the correct calculation to find the energy, in kJ, for a photon of blue light given the wavelength ƛ = 550 nm.
h = 6.626 x 10−34J s; c = 2.988 x 108 m s-1
3.60 x 10-19
3.60 x 10-31
3.60 x 10-22
6.63 x 10-37
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Successive ionisation energies for an element, Y, are shown in the table below.
Electrons removed |
1st |
2nd |
3rd |
4th |
5th |
Ionisation energy / kJ mol-1 |
736 |
1450 |
7740 |
10500 |
13600 |
What is the most likely formula for the ion of Y?
Y+
Y2+
Y3+
Y4+
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Values for the successive ionisation energies for an unknown element are given in the table below.
First ionisation energy / kJ mol-1 |
Second ionisation energy / kJ mol-1 |
Third ionisation energy / kJ mol-1 |
Fourth ionisation energy / kJ mol-1 |
420 |
3600 |
4400 |
5900 |
In which group of the periodic table would the unknown element be found?
1
2
13
14
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The graph shows the first ionisation energies of some consecutive elements
Which statement is correct?
Y is in group 13
Y is in group 10
X is in group 15
X is in group 18
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Which transition on the diagram corresponds to the ionisation of hydrogen in the ground state?
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Element X is in period 2 and has the first seven ionisation energies in kJ mol-1 as shown.
1300 |
3380 |
5330 |
7460 |
11 010 |
13 320 |
71 200 |
What is the electronic configuration of element X?
1s2 2s2 2p4
1s2 2s2 2p2
1s2 2s2 2p3
1s2 2s2 2p6
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For the successive ionisation energies of oxygen, where would the highest jump be expected to occur?
second ionisation energy
first ionisation energy
seventh ionisation energy
sixth ionisation energy
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Which species produces a half-filled set of p orbitals on losing an electron?
Li+
F
N
N-
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Which statement explains why electrons pair up in orbitals before occupying an orbital of a higher energy level?
the energy from repulsion is greater than the jump to a higher orbital
electrons occupy higher energy orbitals before lower energy orbitals
electrons in lower orbitals have higher energies
the energy from repulsion is less than the jump to a higher orbital
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Which equation is correct for the third ionization energy for the element nitrogen?
N+(g) → N4+(g) + 3e-
N2+(g) → N3+(g) + e-
N(g) → N3+(g) + 3e-
N3+(g) → N4+(g) + e-
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A line emission spectrum occurs when
electrons release energy as they move from high to low energy levels
electrons release energy as they move from low to high energy levels
electrons absorb energy as they move from high to low energy levels
electrons absorb energy as they move from low to high energy levels
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A spectral line that would be found in the visible spectrum of the hydrogen emission spectrum would be
n1 → n2
n2 → n3
n3 → n2
n3 → n∞
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Which statement is true about the spectra shown?
All the lines in R have the same energy
Q and S could represent line emission spectra
Only S could represent a line emission spectrum for hydrogen
P indicates the element has 4 pairs of electrons at different energy levels
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The energy absorbed at the limit of convergence for helium is 19.6 x 10-18 J per atom.
Which calculation would be used to calculate the wavelength, in m, for this electron transition?
(c = 3.00 x 108 ms-1, h = 6.63 x 10-34 Js)
8.89 x 1024
1.01 x 10-8
4.33 x 10-59
2.31 x 1058
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The first ionisation energies (in kJ mol-1) of five successive elements are:
2081, 496, 738, 578, 787
What could these elements be?
First five elements in a period
Second to the sixth elements in a period
Last four elements of one period and the first one of the next period
Last element of one period and the first four elements of the next period
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A period 3 element forms an oxide M2O3.
Which represents the first four successive ionisation energies of M?
Ionisation energy / kJmol-1 |
First | Second | Third | Fourth | |
A. | 496 | 4560 | 6940 | 9540 |
B. | 578 | 1820 | 2740 | 11600 |
C. | 1012 | 1907 | 2914 | 4964 |
D. | 736 | 1450 | 7740 | 10500 |
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Between which ionisation energies of silicon will there be the greatest difference?
Between the second and fourth ionisation energies
Between the first and third ionisation energies
Between the fourth and fifth ionisation energies
Between the fifth and sixth ionisation energies
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