STRUCTURE OF THE ATOM

INTRODUCTION

1. ------------- and ---------------- are the fundamental building blocks of matter.
2. What was the major challenge faced by the scientists before 19th century regarding atoms?

CHARGED PARTICLES IN MATTER

3. An atom is ------------ and consists of -------------- particles.
4. The electron was identified by ----------------.
5. Who discovered the presence of new radiations even before the electrons were found?
6. What are canal rays?
7. These rays were ----------------- charged radiations.
8. What is proton? What are its characteristics?
9. Electron is represented as --------- and proton as -------------.
10. What can you say about the mass of electron?
11. What can you say about the mass of proton?
12. Protons and electrons mutually balance their charges. True or False?

THE STRUCTURE OF AN ATOM

13. According to Dalton's theory atom is indivisible and indestructible. True or False?
14. What lead to the failure of Dalton's theory of atom which states that atom is indivisible an indestructible?
15. Who was the first one to propose a model for the structure of an atom?

THOMSON'S MODEL OF AN ATOM

16. Thomson's model of an atom is similar to that of a ---------------.
17. The electrons were like ----------------.
18. How can you connect watermelon and an atom?
19. How are the electrons studded in an atom?
20. What are the proposals of Thomson?
21. What were the drawbacks of Thomson's model?

RUTHERFORD'S MODEL OF AN ATOM

22. Rutherford concentrated more on the arrangement of -------------- in an atom.
23. In his experiment fast moving -------------- were made to fall on a thin gold foil.
24. Why did he select a gold foil? Explain the nature of the gold foil selected.
25. Write a note on the alpha particles used in the experiment.
26. Why didn't he expect large deflections?
27. What were the observations made by Rutherford?
28. What were his words on the observation?
29. Describe a suitable experiment in an open field equivalent to Rutherford's experiment?
30. What were the conclusions made by Rutherford?
31. What are the features of Rutherford's atomic model?

DRAWBACKS OF RUTHERFORD'S MODEL OF THE ATOM

32. The revolution of the electron in a circular orbit is not expected to be -------------.
33. Describe the drawbacks of Rutherford;s model of atom.

BOHR'S MODEL OF THE ATOM

34. What were the postulates of Bohr's model of atom?

NEUTRONS

35. Who discovered neutron?
36. What are the new aspects discovered by J. Chadwick?
37. Neutrons are present in the nucleus of all atoms except ---------------.
38. How can you calculate the mass of an atom?

HOW ARE ELECTRONS DISTRIBUTED IN DIFFERENT ORBITS(SHELLS) ?

39. Who suggested the distribution of electrons into different orbits?
40. What are the rules followed for writing the number of electrons in different energy levels / shells?
41. Have an idea of the fig. 4.4.

VALENCY

42. What are valence electrons?
43. From the Bohr-Bury scheme we know that the outermost shell of an atom can accomodate a maximum of ------------------ electrons.
44. Which atoms show little chemical activity?
45. When can the combining capacity or valence be zero?
46. Define 'comibining capacity'.
47. What is an octet?
48. How is an octet achieved?
49. How can you calculate the valency?
50. What is the different way of calculating valency? Why is this way needed?
51. Go through the table 4.1.

ATOMIC NUMBER AND MASS NUMBER

ATOMIC NUMBER

52. It is the number of ----------- of an atom, which determines its atomic number.
53. Atomic number is denoted by the letter ----------.
54. All atoms of an element have the same atomic number. True or False?
55. Elements are defined by the number of ---------- they possess.
56. Why is Z=1 in a hydrogen atom?
57. Define atomic number.

MASS NUMBER

58. Mass of an atom is practically due to ----------- and -------------- alone.
59. What are nucleons? Why are they called so?
60. The mass of an atom resides in its --------------.
61. Find out the mass of an atom giving an example.
62. Define mass number.
63. How would you represent thbe atomic number, mass number and symbol of an element? Give example.

ISOTOPES

64. Define isototopes. Give example.
65. Define hydrogen atom as an isotope.
66. What are the three isotopes of hydrogen atom?
67. The chemical properties of isotopes are -------------, but their physical properties are ----------------.
68. What are the isotopes of chlorine atom?
69. Describe an experiment to to find out which of the isotope is to be considered for calculating the mass of chlorine atom.
70. How are the special properties of some isotopes useful in different fields?

ISOBARS

71. What are isobars? Explain with example.

ATOMS AND MOLECULES - PART II

ATOMIC MASS

43. Define atomic mass.
44. The theory of atomic mass could well explain the law of -----------------.
45. Scientists could measure the atomic mass of an atom. True or False?
46. What are relative atomic masses?
47. How were relative atomic masses determined?
48. Expand 'amu'.
49. What was initially taken by scientists as the atomic mass unit?
50. Why was oxygen selected for this purpose? Give the two reasons.
51. In 1961, what was universally accepted the amu?
52. Define atomic mass unit.
53. Explain the theory of amu using the illustration of the fruit seller selling watermelon using a standard weight.
54. Define relative atomic mass.
55. Table 3.2 - Learn the atomic masses of the given elements.

HOW DO ATOMS EXIST?

56. Atoms of most elements are not able to exist dependently / independently.
57. Atoms form ----------- and --------------.
58. Molecules or ions ------------------------------------ to form matter.

WHAT IS A MOLECULE?

59. A molecule is a group of --------------- that are ------------- together.
60. Define molecule.
61. Atoms of the ------------------- or of ------------ can join together to form molecules.

MOLECULES OF ELEMENTS

62. The molecules of an element are constituted by the same / different type of actions.
63. Molecules of many elements are made up of  -------------------- of that element.
64. What is a diatomic molecule? Give example.
65. What is the difference in molecules of most of the non-metals. Explain with an example.
66. What is atomicity?
67. Explain the structure of atoms in metals and some particular elements.
68. Table 3.3. Learn the atomicity of the given elements.

MOLECULES OF COMPOUNDS

69. Atoms of different elements join together in ---------------- to form molecules of compunds.
70. Table 3.4. Be familiar with the molecules of some given compunds.
71. Find out the ratio by number of atoms for water.

WHAT IS AN ION?

72. What are known as ions?
73. An ion is a ------------- particle and can be -------------- or ------------------ charged.
74. A negatively charged ion is called --------------.
75. A positively charged ion is called ----------------.
76. Explain anion and cation giving examples.
77. Ions may consist of  ----------------- or -------------------- that have a net charge on them.
78. What is a polyatomic ion?
79. Table 3.5. Be familiar with the given ionic compunds.

WRITING CHEMICAL FORMULAE

80. What is a chemical formula?
81. To write the chemical formulae for different compunds we need to learn the -------------- and ---------------------- of the elements.
82. Define valency.
83. How can be valency used?
84. ------------------ can be considered as hands or arms of that atom.
85. Learn the illustration of octopus to have a better understanding of the valency and chemical formulae.
86. Table 3.6. Be familiar with the names and symbols of some ions.
87. What are the rules you have to follow while writing chemical formulae?
88. The valencies or charges on the ion must ---------------.
89. In a chemical formula, what should be written first? Why? Explain with an example.
90. What do you know of the brackets in a chemical formula?

FORMULAE OF SIMPLE COMPOUNDS

91. What are binary compunds?
92. Learn how to write the chemical formulae through the illustrations given in page 38 and 39.

MOLECULAR MASS AND MOLE CONCEPT

93. What is molecular mass?
94. Molecular mass is expressed in ------------------ units.
95. Learn how to calculate the relative molecular mass of different compunds.

FORMULA UNIT MASS

96. What is formula unit mass of a substance?
97. Formula unit mass is calculated in the same manner as molecular mass is calculated. True or False?
98. Calculate the formula unit mass of Sodium Chloride.

MOLE CONCEPT

99. What was the necessity to introduce the new unit mole?
100. What is mole?
101. The number of particles present in 1 mole of any substance is fixed with a value of --------------.
102. What is called the Avogadro Constant or Avogadro number?
103. The name Avogadro honours the Italian Scientist --------------.
104. The mass of 1 mole of a particular substance is fixed. True or False?
105. How is the molar mass calculated? Give an example.
106. Molar mass of atoms is also known as ------------------------.
107. The atomic mass of hydrogen is 1 u. The gram atomic mass of hydrogen = ---------------.
108. Why is mole the counting unit of the chemists?
109. The word mole is derived from Latin and it means ------------- or ---------------------.
110. Learn the illustrations given in page 41 and 42.

ATOMS AND MOLECULES – PART I

1.      The idea of divisibility of matter was considered in India during -----------------.

2.      Who was Maharishi Kanad? What was his theory?

3.      What is padarth?

4.      What is Parmanu?

5.      How did Pakudha Katyayama elaborate the theory of divisibility?

6.      Define the divisibility theory proposed by Democritus and Leucippus.

7.      Name the two laws of chemical combination established by Antoine L. Lavoisier.

8.      Who formulated the two laws of chemical combination?

9.      Explain law of conservation of mass with an experiment.

10.  Define law of conservation of mass.

11.  Define law of constant proportions.

12.  In water, the ratio of mass of hydrogen to the mass of oxygen is always --------------.

13.  If 9 g of water is decomposed ------------------- of hydrogen and --------------- of oxygen are always obtained.

14.  In ammonia, nitrogen and hydrogen are always present in the ratio ----------------.

15.  The law of constant proportions is also known as ------------------------.

16.  Define Proust’s theory of law of constant proportions.

17.  How did Dalton formulate his theory to answer the initial questions regarding law of constant proportions?

18.  What are atoms?

19.  Where does the name ‘atom’ derived from?

20.  Dalton’s theory of atoms was based on the law of ---------------------.

21.  Dalton’s atomic theory provided an explanation for the law of -------------------- and the law of -------------------------.

22.  Describe the postulates of Dalton’s atomic theory.

23.  All matter is made of tiny particles called -----------------.

24.  Atoms are ------------------ particles. They cannot be ---------------- or ----------------- in a chemical reaction.

25.  Atoms of a given element are -------------------- in mass and chemical properties.

26.  Atoms of different elements have ---------------------- masses and chemical properties.

27.  Atoms combine in the ratio of ----------------- to form ------------------.

28.  The -------------------- and ---------- are constant in a given compound.

29.  Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass?

30.  Which postulate of Dalton’s theory can explain the law of definite proportions?

31.  Atomic radius is measured in -------------------.

32.  1m = --------------- nanometer / nm.

33.  ---------------- was the first scientist to use the symbols for elements in a specific sense.

34.  Berzilius suggested that the symbols of elements be made from -------------------------- of the name of the elements.

35.  In the beginning the names of elements were derived from the ------------------------- and --------------------------------.

36.  In the beginning the name of copper was derived from the word ---------------.

37.  What was the confusion that arose while elements were given names from the places where they were first found and their colours?

38.  Expand IUPAC.

39.  Which organization approves the names of elements nowadays?

40.  The first letter of a symbol is always written in ---------------------- and the second letter in ---------------------------.

41.  Explain how symbols are formed by IUPAC.

42.  Learn the symbols of all important elements.