atomic structure (student)_2014

7/25/2019 Atomic Structure (Student)_2014

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Atomic Structure_201412

Topic: Atomic Structure

Section A: Multiple Choice Questions

1 Which one of the species has more electrons than neutrons and more

neutrons than protons?

Particle Neutrons NucleonsP 16 33Q- 18 35R2+ 17 34S3- 16 31

A P B Q- C R + D S -

NJC Prelims 2007

2 Beams of particles travelling at the same speed from different sources are

subjected to an electric field as shown in the diagram below. A beam ofneutrons has already been drawn.

Which of the following represent the particles labelled X,Yand Z?

X Y ZA 4He+ 1H+ electronsB 4He+ 2H+ 1H+C 1H+ 2H+ 3H+D 1H+ 2H+ electrons

SRJC Prelims 2007

3 Which species is deflected to the least extent in an electric field?

A 22412Mg

B 32713Al

C 2168O

D 33115P

VJC Prelims 2007

4 Which of the graph represents the first 4 ionisation energies of a Group IIIelement?A

source

+-

neutronsY

X

Z

XX

X

XIE

electrons removed1 2 3 4


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B

C

D

YJC Promos 2007

5 Five ionisation energies, in kJ mol-1, are listed below.864 839 1008 1170 376

What do these values most likely represent?

A First ionisation energies for successive elements in Group V, VI, VII, 0and I.

B First ionisation energies for five elements from Group V, listed in theorder of increasing atomic mass.

C Successive ionisation energies for a Group V element.D Successive ionisation energies for the element of atomic number 5.

MJC Promos 2007

6 For which of the following is the ratio of the second ionization energy to thefirst ionization energy the highest?

A Sodium B Magnesium C Aluminium D ArgonIJC Prelims 2007

7 Figure 1 shows the first six ionisation energies of an element X.

X

X

X

X


IE

X

X

XX

IE


XX X

X


IE


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Figure 2 shows the first ionisation energy of eight consecutive elements(including X) of Period 3.

With reference to Figure 2, which of the options corresponds to the firstionisation energy of element X?

AJC Prelims 2007

8 Which of the following particles has an unpaired electron in the s orbital in itsground state?

A V atom B Cu atom C Mn2+ion D Cr+ionMJC Promos 2007

9 Which one of the following ions has the most number of unpaired electrons?

A Cr3+ B Ni2+ C Ca2+ D Co3+NJC Prelims 2007

10 Which is the correct electronic configuration for Ni in [NiO2]2-?

A 1s22s22p63s23p63d74s1B 1s22s22p63s23p63d84s2C 1s22s22p63s23p63d64s2D 1s22s22p63s23p63d8

TJC Promos 2007

11 Which one of the following particles would, on losing an electron, have a half-filled set of p orbitals?

A C- B F C N- D O+Modified TYS J93 P4 Q2

12 Ions of two isotopes of sulfur are shown below.

31S2 35S2

Which one of the following statements is true?

A The electron arrangement of both ions is 1s22s22p63s23p2.B The 31S2ion has more protons in its nucleus than the 35S2ion.C Both ions have the same number of electrons but different number of

neutrons.D Under the same magnetic field, the 35S2ion will be deflected more than

the31

S2

.JJC Promos 2009


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13 How many 4s electrons are present in Cu and Cu +?

29Cu 29Cu2+

A 1 0B 1 1C 2 0D 2 1

CJC Promos 2008

14 For which of the following pairs does the first species contain more unpairedelectrons than the second species?

A C+, N B O, S2+ C Cr, Fe3+ D Mn4+, CoRJC Promos 2009

15 Which of the following ions has more electrons than protons and more protons

than neutrons? [ H =1

1H; D =

2

1H; T = 3H; C =

12

6C; O =

16

8O ]?

A CO32- B H2DO+ C OH- D TCO3-MJC Prelims 2009

The responses Ato Dshould be selected on the basis of

A B C D

1, 2and 3are correct 1and 2are correct 2and 3are correct Only 1is correct

16 Which particle has a half filled set of p orbitals?

1 O-ion.2 N atom.

3 P atom. CJC Prelims 2007

17 Which statements about the s and p orbitals is/are correct?

1 p orbitals of different quantum numbers have the same shape.2 A p orbital has a higher energy of a s orbital of the same principal quantum

number.3 Each p orbital can contain a maximum of 2 electrons.

AJC Promos 200618 Which of these statements incorrectly describe the outermost subshell of the

phosphorus atom?

1 It has a spherical shape.2 It belongs to the shell with principal quantum number n = 3.3 It is half-filled with electrons.

VJC Prelims 2007

19 Gaseous particleY has n protons and a charge of +2.Gaseous particle Z has (n-1) protons and is isoelectronic withY.Which of the following statements correctly describeY and Z?

1 Y has a smaller radius than Z.2 Y has a higher first ionization energy than Z.

3 Y is less electronegative than Z.AJC Prelims 2007


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20 Which of the following statements concerning O, O and O is/are correct?

1 16O, 17O and 18O have the same electronic configuration.2 First ionization energies of 16O, 17O and 18O are in increasing order.3 There is an increasing number of protons from 16O to 17O to 18O.

AJC Promos 2007

21 Which of the following statements is/are correct for N3-, Mg2+and F- ions?

1 All 3 ions do not contain any unpaired electrons in their valence shells.2 Among the 3 ions, F-ion will be deflected the least in an electric field.3 The ionic size increases in the order of N3-, F-, Mg2+.

CJC Promos 2006

22 Which of the following explain the decrease in first ionisation energy down agroup in a Periodic Table?

1 The nuclear charge is increasing.2 The electron to be ionised becomes progressively further from thenucleus.

3 There are progressively more electrons between the nucleus and theelectron to be ionised.

PJC Promos 2006

23 The first eight ionization energies of an element E(in kJ mol-1) are as follows:

966, 1950, 2730, 4850, 6020, 12300, 15400, 18900Which of the following statements about element Eis/are correct?

1 It is in group V of the Periodic Table.2 It can form a chloride that is trigonal pyramidal in shape.3 It has half-filled p-orbitals.

MJC Promos 2006

24 Use of the Data Booklet is relevant to this question.

An ion X2has 36 electrons and 45 neutrons. Which of the following statementsare true?

1 It is isoelectronic with Rb+.2 It has a larger radius than Sr +.

3 More energy is required to remove an electron from Xthan from X2.

NJC Prelims 2009

Answers to MCQs

1 D 7 B 13 A 19 B

2 D 8 B 14 C 20 D3 A 9 D 15 C 21 B

4 A 10 D 16 C 22 C5 A 11 C 17 A 23 A

6 A 12 C 18 D 24 A


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x

y

z

Section B: Structured Questions

1 (a) There are two stable isotopes of nitrogen in nature, nitrogen14 andnitrogen15.

(i) Define the term isotope. [1]

(ii) Complete the following table with the number of elementary particles(electrons, protons, and neutrons) that are contained in the twoisotopes of nitrogen. [1]

Isotope protons neutrons electrons14N15N

(b) Nitrogen can form an ion which is isoelectronicwith the fluoride ion.

(i) Explain what is meant by isoelectronic. [1]

(ii) State the electronic configuration of fluoride ion. [1]

(iii) Explain why the first ionisation energy of the fluoride ion is more thanthat of the ion of nitrogen. [2]

YJC Prelims 2007

2 P, Q, R and S are a sequence of consecutive elements of increasing protonnumber.

(a) The successive ionization energies, in kJ mol-1 of element Q are givenbelow.

1681 3374 6050 8407 11020 15160 17870 92040 106400Which Group does element Q belongs to? Explain your answer. [2]

(b) P, Q and S form ions that are isoelectronic with atom R.

(i) State the charge on the ions of P, Q and S. [1]

(ii) Arrange the ions of P, Q and S in decreasing ionic radius. [1]

VJC Prelims 2007

3 Fluorine is the most reactive of all elements and even combines with all noblegases except helium and neon. Compounds containing the element fluorine are

commonly called fluorides.

(a) Give the electronic configuration of fluorine,F. [1](b) On the axes below, sketch the shape(s) of the singlyoccupied orbital(s) in

an atom of F at ground state. [2]RJC Prelims 2009


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4 The electronic configuration of sulphur can be represented by 1s 2s 2p 3s 3p .On the axis below, sketch the graph for the first seven ionisation energies of theelement against the number of electrons removed. [2]

RJC Prelims 2007

5 On the grids below, sketch the trend of the successive ionization energies of the

first 10 electrons of a chlorine atom. [3]

HCI Prelims 2007

Ionisation energy/ kJ mol1

0 1 2 3 4 5 6 7No. of electrons removed


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6 The graph below shows the successive ionisation energies of element X.

(a) Identify element Xby writing down its symb ol notationin the form Xab

and

explain how you derive at your answer. [1.5]

(b) Predict the full electronic configuration for atom X. [1]

(c) Describe the general trend of the successive I.E. of X. Give reasons for yourobservation. [2]

SRJC Prelims 2007

7 (a) Write the electronic configuration of sulphur. [1]

(b) Draw five labeled diagrams of the three s orbitals and two p orbitals ofsulphur to illustrate their shapes and sizes. [2]

PJC Prelims 2007

8 (a) Sketch and label all the valence shell orbitals present in the fluorine atom. [2]

(b) The graph below shows the logarithm of successive ionisation energies (I.E)for the first nine electrons in a gaseous atom X. Element Xis in Period 4.

(i) Deduce with reasoning the group number of element X. [2]

(ii) Draw the energy level diagram for element X. [2]MJC Promos 2006

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Ionisationenergy/kJ mol

-1

No. of electrons removed


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9 Hydrogen cyanide gas was the agent used by Germans Nazis for mass murder insome gas chambers during the Holocaust. Inhaling excess hydrogen cyanide gasis fatal as the cyanide ion can bind irreversibly to the iron in hemoglobin in ourblood to form the complex ion, Fe(CN)6

4-. This leads to oxygen gas being unableto bind to hemoglobin in the blood.

Given that the oxidation state of iron in the complex, Fe(CN)64-is +2,

(a) write the electronic configuration of iron in Fe(CN)64-. [1]

(b) draw the energy level diagram showing the electronic configuration of iron inFe(CN)6

4-. [3]TJC Promos 2007

10 In an experiment, a sample of lead was vaporised, ionised and passed throughan electric field. Analysis of the deflection occurring at the electric regionrevealed the following data for a sample of 208Pb2+charged ions. It was observed

that a beam of208

Pb2+

gives an angle of deflection of 8.

(a) Copy the above diagram and sketch to show how the beam of Pb + isdeflected. State its angle of deflection clearly on the diagram.[1]

(b) Predict with reasoning and sketch on the same diagram the angle of

deflection for a sample of 232

16S .

[2]

MJC Prelims 2007

11 (a) Nuclear medicine makes wide use of a metastable form of the isotope of

technetium Tc99

43. The isotope Tc

99

43can be injected into the blood stream as

the compound NaTcO4 to monitor blood flow in some vital internal organs.

Describe the technetium atom, Tc99

43, as fully as you can, including the nature

and location of the sub-atomic particles. [2]

(b) Technetium and manganese are in the same group of the Periodic Table. Inan experiment, a sample of manganese was vaporized, ionized and passedthrough an electric field. Analysis of the deflection occurring at the electric

region revealed that a beam of 255

25Mn gives an angle of deflection of 4.


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(i) Predict with reasoning and indicate on the above diagram the angle

of deflection for a sample of Tc99

43. [2]

(ii) Draw an energy level diagram to represent the electronic configuration

of 255

25Mn . [1]

(c) The diagram below shows successive ionisation energy values for threeunknown elements X,Y and Z in Period 3 of the Periodic Table.

(i) Suggest with a reason the Group which Z belongs to. [1]

(ii) Element X exists as a macromolecule and it is a semi-conductor inelemental form. Suggest an identity for X and hence write its fullelectronic configuration. [1]

(iii) How would you expect the first ionisation energy of nitrogen tocompare with that of elementY? Give reasons to support your answer.

[2]

(iv) Element Y reacts readily with bromine to give YBr5. Suggest whynitrogen does not react similarly to give NBr5. [1]

MJC Promos 2007


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12 In an analytical chemistry laboratory, the plasma torch is often used to ionise avariety of samples during their analyses. In one series of analyses, samples ofelements A-Gwere passed through the plasma torch and their third ionisationenergies were recorded and plotted as shown. The elements A-G haveconsecutive proton numbers below 20 and lies in period 3.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

A B C D E F G

Elements

3rdIonisationEnergy/kJmol-1

(a) Identify the group number to which element Ebelongs. [1]

(b) Hence identify element Eand state its ground state electronic configuration.[2]

(c) Sketch, on the diagram below, how separate beams of A+and Eions wouldbe. [2]

CJC Promos 2009

13 (a) Define the terms [2]

(i) isotope,

(ii) isotopic mass.

(b) particle protons neutrons electrons

P 6 8 6

Q 7 7 10

R 8 7 7

[6]

(i) Give the symbols (showing the nucleon numbers and charges) of thefollowing three particles.

(ii) Use the Data Booklet to identify which are not the usual isotopes ofthe elements concerned.

+

_

Source


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(c) A plasma is a gaseous mixture in which the atoms have been completelystripped of their electrons, leaving bare nuclei. Because of possible use incontrolled nuclear fusion reactions, plasma behavior has been intensivelystudied. When passed between two plates carrying a certain electric charge,

H

1

and He4

nuclei are deflected as follows:[4]

Giving reasons for your answers, suggest

(i) the polarity (+ or -) of plate A,

(ii) why H1 is deflected twice as much as He4 ,

(iii) the angle of deflection of

I: H2 nuclei,

II: He3

nuclei.TYS J2000 P1 Q1

atomic structure (student)_2014

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