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.
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