Exercise- 8th Science, 5. Inside the Atom.
2. Write electronic configuration of sodium.
3. Valency of magnesium is ..... .
4. To control the chain reaction in the nuclear reactor it is necessary to decrease the speed and number of neutrons. For this purpose which two provision is made in a nuclear reactor.
5. Sulphur contains 16 proton and 16 neutrons. What would be its atomic number and mass number?
6. The valency is ...... when electron octet or duplet is complete.
7. How many types of subatomic particles are found in atom?
8. Rutherford took a very thin gold foil and bombarded it with positively charged .... - particles emitted by a radioactive element.
9.What is meant by matter ?
10. According to ....... atomic theory the mass is distributed uniformly in an atom.
11. There is a ..... charged nucleus at centre of an atom.
12. On road sodium vapour lamp gives ....... colour light.
13. 1u = ......... Kg.
14. Atomic number of carbon is 6. How many electrons are there in a carbon atom ?
15. The mass of a neutron is approximately ............ .
16. Write electronic configuration of bromine.
17. Proton and neutrons are the two types of .......... .
18. Which shortcoming of Rutherford’s atomic model was removed by Niels Bohr?
19. To reduce the number of ........ by absorbing them rods of boron, cadmium, beryllium etc. are used as controller.
20. What is an atom ?
21. ‘‘....... of an element is same as the number of its valence electrons if this number is four or less than four.
22. The indivisible particles that constitute matter were named by Kanad Muni as ‘.........’.
23. ........ is an electrically neutral subatomic particle.
24. Which is the outermost shell of fluorine atom ?
25. The ....... is a fundamental property of an element and its chemical identity.
26. Iodine -131 is used in the treatment of ......., disease of thyroid gland.
27. The number of protons in the nucleus of an atom is the ............ of that element and is denoted by the ‘Z’ .
28. The radioactive isotope ....... is used for determining the age of archeological objects.
30. Which is the outermost shell of sodium atom ?
31. ........ means the number of chemical bonds formed by an atom.
32. ........ is a negatively charged subatomic particle and is denoted by the symbol ‘e-’.
33. ‘ Atomic nuclei of all the elements except ........... contain neutrons.
34. Almost the entire mass of the atom is concentrated in the ....... .
35. The smallest particle of matter was name by Democritus as ‘........’.
36. There is an ........ between the revolving electron and the atomic nucleus.
37. According to ...... atomic theory matter is made of atoms and atoms are indivisible and indestructible.
38.Uranium - ....... is used for nuclear fission and production of electricity.
39. Sir J. J. Thomson discovered the ....... .
40. Some radioactive isotopes like ...... are used in the medical treatment of fatal diseases like cancer.
41. Write three isotops of hydrogen.
42. Valency of chlorine is ..... .
43. The atomic number and mass number of magnesium are 12 and 24 respectively. How will you show this by the convention symbol ?
44. The nucleus of carbon contain ..... neutrons.
45. Why the atom is electrically neutral?
46. Atomic structure was studied at depth with the advent of a new branch of science called ........ mechanics.
47. Atom of all the elements except ........ have tendency to combine with other atoms.
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