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SECTION 1
FUNDAMENTALS OF MATTER
1986 1.
The atomic structure of an element is: Number of electrons Number of protons Number of neutrons
17 17 19
In its compounds, this element is most likely to have an oxidation number of A. +2. B. +1. C. -1. D. -2. 2.
8.
The melting points of diamond, sodium chloride and potassium increase in the order: A. diamond, sodium chloride, potassium B. potassium, sodium chloride, diamond C. sodium chloride, diamond, potassium D. sodium chloride, potassium, diamond An element X forms an oxide X2O3 which contains 30% of oxygen by mass. The relative atomic mass of X is (Relative atomic mass of oxygen = 16) A. 11. B. 27. C. 31. D. 56.
11. Which of the following molecules has the greatest number of lone pairs of electrons? A. ammonia
B. hydrogen fluoride C. methane D. water 37. The melting points of some chlorides are given below: NaCl 801°C MgCl2 712°C SiCl4 -68°C Which of the following statements would be consistent with the above data? (1) NaCl can conduct electricity at 801°C. (2) MgCl2 is a liquid at 600°C. (3) SiCl4 is a covalent compound. A. (1) only B. (2) only C. (1) & (3) only D. (2) & (3) only 81 38. Bromine exists in two isotopic forms, 79 35 Br and 35 Br . The relative atomic mass of bromine is 79.9. Which of the following statements is/are correct? (1) The relative abundance of each isotopic form is about the same. (2) The two isotopes have different numbers of protons. (3) The two isotopes have different numbers of neutrons. A. (2) only B. (3) only C. (1) & (2) only D. (1) & (3) only
43. At room temperature and pressure, iodine exists as (1) molecules held together by covalent bonds. (2) ions in a lattice. (3) molecules held together by van der Waals’ forces.
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A. B. C. D.
(1) only (3) only (1) & (2) only (2) & (3) only
B. conducts electricity when it is in the molten state. C. has a formula A2B. D. is insoluble in water. 28.
44. Sulphur is classified as a non-metal because (1) it has a low density. (2) it forms acidic oxides. (3) it is a non-conductor of electricity in the solid state. A. (1) only B. (3) only C. (1) & (2) only D. (2) & (3) only 48. Astatine (At) is a halogen at the bottom of group VII in the Periodic Table. From knowledge of trends in periodicity, which of the following predictions is UNLIKELY? A. It will form an anion At-. B. It will exist as a solid at room temperature. C. It will be readily soluble in water. D. It will exist as diatomic molecules in the gaseous state. 1987 1.
2.
The atomic number of an element X is 12. The atomic number of another element with chemical properties similar to those of X is A. 8. B. 16. C. 20. D. 22. The atomic numbers of two elements A and B are 20 and 17 respectively. The compound formed between A and B A. is a liquid at room temperature.
If the glass plate in the above diagram is removed, a brown coloration gradually appears in gas jar Y because A. nitrogen dioxide is lighter than air. B. nitrogen dioxide reacts with air to form a brown compound. C. molecules of both gases are in continual random motion. D. weak intermolecular forces exist between air molecules and nitrogen dioxide molecules. 31. Silicon has a higher melting point than aluminium because silicon (1) is a non-metal. (2) has a giant covalent network structure. (3) has a higher relative atomic mass. A. (2) only B. (3) only
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C. (1) & (2) only D. (1) & (3) only 39. In industry, graphite electrodes are always used in the electrolysis of concentrated sodium chloride solution because graphite (1) is cheap. (2) conducts electricity. (3) is chemically inert. (4) is a reducing agent. A. (1) & (3) only B. (2) & (4) only C. (1), (2) & (3) only D. (2), (3) & (4) only 40. The production cost of helium is much higher than that of oxygen because (1) helium is very difficult to liquefy. (2) helium is very inert. (3) there is not much helium in air. A. (1) only B. (1) & (2) only C. (1) & (3) only D. (2) & (3) only 49. In which of the following pairs would both members have the same electronic configuration? A. O2-, F B. Ne, Na+ C. Na, Mg2+ D. S, Cl43. Which of the following statements is/are true for chlorine, bromine and iodine? (1) They exist as diatomic molecules at room temperature and pressure. (2) Their oxidizing power decreases as their relative molecular masses increase.
(3) Their colours darken as their relative molecular masses increase. A. (1) only B. (1) & (3) only C. (2) & (3) only D. (1), (2) & (3) 1988 1.
Which of the following statements concerning the Periodic Table is correct? A. In any group, the atomic size of the elements decreases with increasing atomic number. B. In any period, the metallic character of the elements increases with increasing atomic number. C. Group I elements are oxidizing agents and Group VII elements are reducing agents. D. The compounds formed between Group IV elements and other elements are mostly covalent.
2.
The atomic number and mass number of a sodium atom are 11 and 23 respectively. Its nucleus contains A. 11 neutrons and 12 protons. B. 12 neutrons and 11 protons. C. 12 neutrons and 23 protons. D. 23 neutrons and 11 protons.
3.
Which of the following compounds has the largest number of lone pairs of electrons on the central atom? A. CCl4 B. NH3 C. H2S D. CO2
15. Which of the following solutions is a weak electrolyte? A. 0.1 M glucose solution
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B. 2.0 M propanoic acid C. 0.5 M ammonium chloride solution D. 0.2 M sodium carbonate solution
B. 43. C. 62. D. 67. 3.
17. A potential difference is applied between the electrodes as shown in the above set-up. After some time a yellow colour is observed near the positive electrode. This is because A. copper(II) chromate is yellow in colour. B. copper(II) ions and chromate ions repel each other under the influence of the electric field. C. copper(II) ions move away from the positive electrode, leaving chromate ions behind. D. chromate ions move towards the positive electrode.
33. Which of the following exists as discrete molecules at room temperature and pressure? (1) graphite (2) bromine (3) hydrogen chloride (4) calcium chloride A. (1) & (4) only B. (2) & (3) only C. (1), (2) & (3) only D. (2), (3) & (4) only 34. Which of the following electronic structures is/are correct? (for N2) (1) N N
1989 1.
Solid lead(II) bromide is a non-conductor of electricity because A. it is a covalent compound. B. it is not soluble in water. C. the lead and bromide ions are not freely moving. D. lead conducts electricity but bromine does not.
With reference to the data given in the table: Element X Y
Atomic number 12 9
Mass number 24 19
The relative molar mass of the compound formed between X and Y is A. 21.
2-
(2)
S
(3) O A. B. C. D.
C O (for CO2) (1) only (1) & (2) only (2) & (3) only (1), (2) & (3)
(for S2-)
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(1) the size of the atoms. (2) the melting point of the elements. (3) the oxidizing power of the elements. Which of the following combinations is correct? A. (1) & (2) only B. (1) & (3) only C. (2) & (3) only D. (1), (2) & (3)
1990 1.
Which of the following elements in the third period of the Periodic Table is the strongest reducing agent? A. sodium B. sulphur C. chlorine D. aluminium
2.
A cation of a certain element has 22 electrons and a mass number of 55. If the charge on the cation is +3, the number of neutrons in the cation is A. 19. B. 23. C. 25. D. 30.
3.
The atomic numbers of element X and element Y are 13 & 16 respectively. The formula of the compound formed between X and Y is likely to be A. XY2. B. X2Y. C. X2Y3. D. X3Y2.
4.
5.
Which of the following combinations concerning the isotopes of an element is correct? No of protons No of neutrons No of electrons A. same different same B. same same different C. different same different D. same different different In going down the group VI elements of the Periodic Table, there is an increase in
25. Bromine has a low melting point because A. it is a non-metal. B. it is a member of the halogen family. C. the atoms in each bromine molecule are bonded together by a covalent bond. D. the bromine molecules are attracted together by van der Waals’ forces.
26. Dry zinc chloride solid is a non-conductor of electricity because A. it is a non-electrolyte. B. it exists as molecules. C. its ions are not mobile. D. metallic bonding is not present. 1991 Directions: Questions 1 and 2 refer to the following table. Element Atomic number 1.
W 4
X 8
Y 14
Z 20
Which of the following elements are likely to be metals?
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A. B. C. D. 2.
4.
W and X W and Z X and Y Y and Z
A. B. C. D.
The formula of the compound formed between X and Z is likely to be A. XZ. B. XZ2. C. X2Z. D. X2Z3. Which of the following groups of ions/atoms has the same number of electrons? A. K+, Ca2+ B. Cl-, S C. H+, He D. O2-, Ar
2.
Rubidium (Rb) is a group I element below potassium in the Periodic Table. Which of the following statements about rubidium is correct? A. Rubidium forms an acidic oxide. B. Rubidium is more reactive than potassium. C. Rubidium can be obtained from its oxide by reduction with carbon. D. The formula for rubidium chloride is RbCl2. X and Y are elements. The melting points of their chlorides are given below:
Chloride of X Chloride of Y
Melting point (°C) 772 -68
Which of the following statements is correct?
Which of the following electron diagrams is correct? A. F F B.
O
C.
N N
-
D. He He 4.
1992 1.
3.
Both X and Y are metals. The chloride of Y is a solid at room temperature. The chloride of X conducts electricity in the solid state. The chloride of Y is a covalent compound.
Consider the following table: Element Atomic number
W 9
X 10
Y 14
Z 19
Which of the following elements is likely to be an oxidizing agent? A. W B. X C. Y D. Z 30. The atomic number and mass number of element E are 8 & 17 respectively. What are the numbers of protons & neutrons in an atom of E? No. of protons No. of neutrons A. 8 9 B. 8 17 C. 9 8
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D.
9
17
33. Which of the following ions is/are coloured? (1) Pb2+(aq) (2) Cr3+(aq) (3) MnO4-(aq) A. (1) only B. (3) only C. (1) & (2) only D. (2) & (3) only
24. There is a gradual change in the properties of halogens from chlorine to iodine. Which of the following properties are in the order chlorine < bromine < iodine (1) oxidizing power (2) density (3) boiling point A. (1) & (2) only B. (2) & (3) only C. (1) & (3) only D. (1), (2) & (3)
1993 1.
2.
4.
Which of the following pairs of atoms/ions has the same number of electrons? A. Mg2+ & F B. Cl- & Ne C. K+ & O2D. Cl- & S2The elements, sodium to chlorine, in the third period of the Periodic Table show a gradual change in properties. Which of the following changes is correct? A. Their melting points increase. B. Their ability to gain electrons increases. C. Their oxides change from acidic to basic. D. Their chlorides change from covalent to ionic. The element with atomic number 11 will combine most readily with the element whose atomic number is A. 12. B. 13. C. 17. D. 18.
1994 1.
2.
If the atomic number of an element X is 13, the formula of its oxide is A. XO2. B. XO3. C. X2O3. D. X3O2. Consider the information given in the table below: Atom P Q R S T
Atomic number 6 7
Mass number 14 14 13 18
10
Which of the following atoms are isotopes? A. P and Q B. P and R C. R and S D. S and T
No. of neutrons 7 10 10
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3.
Which of the following molecules has the greatest number of lone pairs of electrons? A. fluorine B. hydrogen C. nitrogen D. oxygen
Direction: Questions 6 and 7 refer to the following experiment:
C. yellow D. black 7.
The main aim of this experiment is to show that A. ions exist in silver nitrate solution and sodium iodide solution. B. sodium ions can react with nitrate ions. C. silver ions can react with iodide ions. D. potassium nitrate is an electrolyte.
36. X, Y and Z are three different elements. The electronic diagram (showing electrons in the outermost shells only) of the compound formed by X, Y and Z is shown below:
A drop of silver nitrate solution and a drop of sodium iodide solution are placed respectively at X and Y as shown in the diagram below:
After the circuit has been closed for some time, a coloured patch is formed between X and Y. 6.
What is the colour of the patch? A. brown B. purple
Which of the following statements are correct? (1) There is one electron in the outermost shell of an atom of X. (2) There are five electrons in the outermost shell of an atom of Y. (3) There are eight electrons in the outermost shell of an atom of Z. A. (1) & (2) only B. (1) & (3) only C. (2) & (3) only D. (1), (2) & (3)
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