Danyal Education Danyal Education Atomic Structure ... · PDF fileAtomic Structure Assignment 1 (Pure and Combined) U U. 34 . Theme . 2 . I . Atomic . Structure . ond . Stoichiomelry.

For each of the questions, there are four possible choices.Ghoose the one you consider corect and record your choice.

d Which of the following statements about an atom is correct?

A The numbers of protons and electrons determine its mass.

B lts nucleon number is the total number of neutrons in itsnucleus.

C lt is electrically neutral as there are equal numbers ofprotons and neutrons.

D The number of electrons and their arrangement determineits chemical properties. (

)

d2. Which of the following comparisons describes correctly theparticles of an atom?

A An electron has a positive charge and a mass much lessthan a neutron.

B An electron has a negative charge and a mass equal tothe mass of a proton.

C A proton has a positive charge and a mass larger thanthe mass of a neutron.

D A neutron has a neutral charge and a mass larger thanthe mass of an electron. ( )

d3. What happens when an oxygen atom becomes an oxygenion?

A lt gains a positive charge.B lts atomic mass decreases.C lts nucleon number increases.

D lts atomic number remains the same. ( )

d4. Which of the following ions has the correct number ofelectrons, neutrons and protons shown?

lon Electrons Neutrons Protons

A i3s" tb 20 14

B 2512 lvlg'* 10 13 12

C ?1

H+ 1 1 1

D'3 r- B i0 o

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Befer to the following t0 answer questions 5 and 6

The diagrams below show two particles, X and Y.

5. Which of the following is true about X and Y?

A They have different charges.

B They belong to the same element.C They belong to elements in the same group of the Periodic

Table.

D They belong to elements in the same period of the PeriodicTable. (

)

6. Which of the following gives a correct representation of theparticles X and Y?

7. Which of the following does not have the same number ofelectrons as an atom of argon?

AS} BC/C Caz* D A/3r (

)

\V0 B. Which of the following consists of particles with the same

electronic conf iguration?

A F,Cl ,Br B S,_,C/-,K*C Be2*, [/g2*, C6z* D H-, H, H- (

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34 Theme 2 I Atomic Structure ond Stoichiomelry

U L X and Y are two different atoms with the same nucleon

number. Which of the following is true about X and Y?

A They have similar chemical properties.

B They are isotopes of the same element.C They have the same number of neutrons.

D They cannot belong to the same element. ( )

15. Which atom has the same electronic configuration as theselenium ion?

A Argon B Bromine

C Krypton D Arsenic ( )

16. Which particle has a different number of electron shells fromthe others?

A Al3r B 02_

CCr DNe ( )

17. Which particle has a different number of electron shells fromthe others?

A Sn2t B BrCSrz. DKr ( )

18. The table bel0w shows the composition of two particles, Xand Y.

Which of the following statements about X and Y are true?

I They have different charges.

ll They have similar chemical properties.

lll They are isotopes of the same element.

lV They belong to elements from different groups of thePeriodic Table.

A I and lll only B I and lV only

C ll and lV only D l, ll and lll ( )

19. Carbon has three naturally occurring isotopes, carbon-l2,carbon-l 3, and carbon-1 4.

Which of the f0llowing statements about carbon-14 is

incorrect?

A lt is found in carbon dioxide in the atmosphere.

B lt reacts with oxygen to form carbon monoxide.

C lt has the same electronic structure as the other isotopes.

D lt contains the least number of neutrons amongst thethree isotopes of carbon. ( )

20. Three elements, X, Y and Z, have consecutive increasingatomic numbers.

lf element Y is a noble gas, what will be the symbol for theions formed by elements X and Z in their compounds?

A X- and Z* B Xts and ZhC X-andZ D X2+and?? ( )

10. What can y0u conclude about the following atoms?

?3S ltcl ?3Ar ?3K

A They have the same atomic mass.

B They have the same number of neutrons.

C They have the same number of electron shells.

D They have the same total number of electrons, protons

and neutrons. ( )

11. Titanium has five stable isotopes and shows three oxidationstates, +2, +3 and +4. Below is the particle formed from themost abundant isotope.

tlli*Which of the following is/are true about the particle shown?

I lt has 26 protons.

ll lt has 26 neutrons

lll lt has 18 electrons.

A lll only B I and ll onlyC ll and lll only D l, ll and lll ( )

U,r. *n,rn particle is represented in the diagram shown?

U 13. An isotope of element X has 12 neutrons and 11 protons.

Which of the following shows the correct symbol of the ron

formed by X?

A ??r e 11x-

c??x oiSx- ( )

14. 852 and 872 are isotopes of an element Z.

How is the ion formed by B5Z different from the ion formed

bY87z?

A lt has 2 less neutrons and 2 less electrons.

B lt has 2 less neutrons but no less electrons.

C lt has 2 less protons and 2 less electrons.

D lt has 2 less protons but no less electrons. ( )

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21. Which statements about the ions of the Group ll elementsis/are conect?

I All the ions have 2 electrons in the outermost shell.ll All the ions contain an even number of electrons.lll All the ions contain more pr0t0ns than electrons.lV All the ions have electronic configurations identical to

those of noble gases.

A I only B l, ll and lll onlyC l, ll and lV only D ll, lll and lV only ( )

22. XandY are two particles having the same number of neutronsand protons but different number of electrons.

Which of the following may be true of X and Y?

A They are isotopes of the same element.B They are an atom and ion of the same element.C They are an atom and ion of different elements.D They are oppositely charged ions of different elements.

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UnitS I :,'t:;;.;.,..t:;-':;:,'. , 35

Wru An early model of the atom, as shown below, was proposed

by J. J. Thomson in 1 904. He described the structure of theatom as a positively charged sphere with small, negativelycharged electrons embedded inside. These electrons are freeto circulate in rings within the sphere.

positivelycharged sphere

negativelycharged electrons

Which of the following provide a correct comparison ofThomson's model with the currently accepted model of theatom?

I Both conectly describe the atom as consisting of electrons

and protons.

ll Both correctly describe the electrons as freely crrculatingrnside the atom.

lll The currently accepted model describes the positivecharges as being concentrated in a tiny core of the atom.

lV The currently accepted model describes the presence ofneutral particles which contribute partially to the mass

of the atom.

A lll and lV only B l, ll and lll onlyC ll, lll and lV only D l, ll, lll and lV (

)

Befer to the following t0 answer questions 21 and28.

lVost elements consist of two or more isotopes. 0f the many knownisotopes of elements, only about 275 of these are stable. The restare unstable and disintegrate spontaneously to form other elements.

It is found that the stability of an atom depends on its neutron-to-proton ratio. The following graph shows the plots of number ofneutrons t0 protons for the known stable isotopes of elements.

Which of the following is not true?

A Atoms of the same element may have different masses.

B Atoms of different elements may have the same number

of neutrons.

C Atoms of different elements may lose or gain the samenumber of electrons.

D Atoms of elements from the same group of the Periodic

Table have the same number of protons. ( )

The particle X3 contains 15 particles in its nucleus and 10

electrons.

Which of the following shows the numbers of neutrons andprotons found in its nucleus?

Neutrons Protons

A B lB l B

C 6 ID

tr 10

25. Lithium is a soft and reactive metal. lts atoms have anelectronic configuration of 2.1.

Which of the following statements are correct?

I The lithium atom has 1 valence electron.ll The lithium ion has an electronic configuration of 2.2.lll The electrons in the atom are in two different energy

levels.

lV All the electrons shown take part in bonding with otheratoms.

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110

100

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C l, ll and lV only

B I and lV onlyD l, ll, llland lV

l0 20 30 40 50 60 70 80 90Number of protons, Z

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36 lheme 2 I Atomic Struclure ond Stoichiometry

W27. Which of the following is not a valid conclusion drawn fromthe graph?

A Unstable isotopes have too many protons and neutrons

in the nuclei.

B Heavier isotopes which are stable have a higher number

of neutrons than protons.

C For stable isotopes, as atomic number increases, thenumber of neutrons increases proportionately.

D Lighter isotopes are most stable when they have an

approximately equal number of neutrons and protons.()

W,, By observing the trend of the behaviour of stable isotopes

from the graph, which of the following isotopes is likely tobe unstable?

A 13c, s f? Na

c 'z88pn o 133sn ( )

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Titanium has five stable isotopes and shows three oxidationstates, +2, +3 and +4. Below is the particle formed from themost abundant isotope.

i:Ti *

Which of the following shows the numbers of protons,

neutrons and electrons of the particle formed by a differentisotope of titanium?

Protons Electr

A ?2 26 19

B 18 20 2?

C 22anLO 20

D 22 22 11

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Naturally_^occurring^oxygen is made up of three stableisotopes: 30, 60, 80.

fydlogep also consists of three naturally occurring isotopes:

I H,iH,iH. The i H andf H isotopes are stable, but the iHisotope is unstable and disintegrates spontaneously.

Water, which is made up of HrO molecules, will consist of a

mixture of these isotopes. Which of the following represents

the lightest, unstable molecular isotopic composition ofwater?

A

C

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D

H]H

H?H

U 30. A particleXcontains 10 electrons, 14 neutrons and l2 protons.

Which of the following shows the numbers of protons,

neutrons and electrons of a particle of an element from thesame group of the Periodic Table as X?

EXTENSION QUESTIO

A 24 30 26

1B 20 20B

C 16 16 1B

20 22 1BD

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Neutrons

Protons Neutrons Electrons

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