C3 Py Pendang

PSPM1

: ATOMIC STRUCTURE

Session 1999/2000 - January Intake Section A 1.

The Brackett series of hydrogen line spectrum is in the infrared region. The wavelength of the third line in the series is 2166 nm. (a)

Why is the hydrogen atomic spectrum exists as lines?

(b)

Explain how the third line of the Brackett series is formed?

(c)

Calculate the energy involved in the formation of the third line of the Brackett series. (9.18×10−20 J)

Section B 2.

By refering to the Bohr’s postulates, explain the formation of line spectrum of the hydrogen atom.

3.

(a) Explain the Aufbau principle, Pauli’s exclusion principle and Hund’s rule, using suitable examples. (b)

What is an orbital?

(c)

Write the electron configuration for a chromium atom, 24Cr. Draw the shape of the orbitals occupied by the valence electron and write the set of four quantum numbers for each valence electron.

Session 1999/2000 - Jun Intake Section A 1.

(a)

Draw the shape of a py and a dxy orbitals with the correct orientation.

(b)

Write a set of possible quantum numbers of a 3dxy orbital.

Section B

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The frequencies for the first five lines in the Balmer series of the atomic hydrogen line emission spectrum are as follows: (4.57, 6.17, 7.31, 7,55 and 7.71)×1014 Hz Copy the energy level diagram below and draw arrows to represent the electron transitions in the hydrogen atom that correspond to the frequencies given. n=8 n=7 n=6 n=5 n=4

n=3

n=2

n=1 Calculate the wavelength of the third line in the Balmer series. 3.

Atomic orbitals are characterised by four quantum numbers. Name the four quantum numbers and state the features of each. Write the electronic configuration of 20Ca and give the corresponding set(s) of four quantum numbers for its valence electron(s).

Session 2000/2001 - January Intake Section A

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1.

Calculate the energy required by an electron in a hydrogen atom, which is promoted from the first orbit to the third orbit.

2.

Explain why the following sets of quantum numbers are not allowed in an atom. (a)

n = 2, l = 1, m = -1, s = 1

(b)

n = 3, l = -1, m = 2, s = +½

Section B 3.

Explain the differences between the emission spectrum in the Lyman and Balmer series.

4.

(a)

What is meant by ionization energy of the hydrogen atom?

(b)

Explain how the ionization energy of the hydrogen atom is obtained from the Lyman series. Calculate the ionization energy of hydrogen atom in kJ mol-1.

5.

Write the ground state electronic configuration of 13Al and 22Ti+.

Session 2000/2001 - Jun Intake Section A 1.

(a)

Arrange the following orbitals in the ascending order of energy levels. 6p, 4d, 4s, 4f, 3p, 3d, 5s

(b)

Predict the most stable oxidation state for the elements X, Y and Z which have the following electronic configuration: X

: 1s22s22p63s23p5

Y

: 1s22s22p63s23p63d54s2

Z

: 1s22s22p63s23p63d14s2

Section B 2.

(a)

Name the quantum number that represents the shape of an orbital.

(b)

The following sets of quantum numbers are the quantum number for the outermost electrons in atom J (3,2,0,-½), (3,2,+1,-½), (3,2,-1,-½)

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i.

Suggest the name of orbitals occupied by the electrons.

ii.

Draw the orbital diagram and write the electronic notation of J.

iii.

If five electrons are removed from J, what is the electronic notation of the ion formed?

iv.

State the type of stability of the ion.

Session 2001/2002 Section A 1.

Give all possible values of l and ml for 3p and 4d orbitals.

Section B 2.

Calculate the wavelength for the third line in the emission spectrum of the Lyman series. Determine the ionization energy of 1 mol of hydrogen atom. (9.72×10-8 m, 1.31×106 J)

Session 2002/2003 Section A 1.

A line emission spectrum of hydrogen atom is observed in the visible light range with the wavelength of 410.2 nm. (a)

What is a line spectrum?

(b)

Name the series of the line spectrum.

(c)

Determine the transition of electron involved.

Section B 2.

An element N has a proton number of 22. Draw the orbital diagram and explain how the Hund’s rule, Pauli exclusion principle and Aufbau principle are used in filling of electrons in the atomic orbitals of N. Draw the orbitals occupied by the last four electrons in N and write the set of quantum numbers of each four electrons.

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Session 2003/2004 Section B 1.

Explain the formation of line spectrum of hydrogen atom in the Balmer series. If the emitted photon has a wavelength of 434 nm, determine the electronic transition that occurs. Calculate the energy of the line with the lowest energy in the Balmer series in kJ mol − 1 .

Session 2004/2005 Section A 1.

Copper is the ninth element in the first row of d block of the periodic table. (a)

Write the electronic configuration of copper according to the Aufbau principle and the actual configuration as determined by experiments.

(b)

Give reason(s) for any anomaly.

(c) Name another transition element which shows similar anomaly and write its electronic configuration showing the anomaly. (ci)

Section B 2.

Explain why an atomic emission spectrum consists of a series of lines.

Session 2005/2006 Section A 1.

The figure below shows the line spectrum of hydrogen atom in the visible region.

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red

blue

indigo

violet

frequency increase (a)

Give the name of this particular series.

(b)

Draw the energy levels in hydrogen atom.

(c)

Show the electronic transitions which produce the above lines.

Section B 2.

State the Aufbau principle and Hund’s rule. Based on the principle and the rule, deduce the electronic configuration of element 26G. Draw the shape of d xy and d x2 −y2 orbitals in 26G and state a possible azimuthal quantum number, l and magnetic quantum number, m for each of the orbitals.

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