1. Define the phases of matter and phase change.
2. What are chemical and physical properties?
3. How do you distinguish a chemical change from a physical change?
4. What kind of change is present in dissolving salt in water? Rusting of iron?
5. What is the difference between an atom and an element?
6.What is the difference between a compound and a molecule?
7. What the difference between a mixture and a compound?
8. How many atoms are in one molecule of H3 PO 4 ?
9. What is an ion?
10. What are ionic and covalent bonds?
11. What are Solute and Solvent?
12. What is Molarity?
13. What is the mass of one mole of water (H2O)?
14. How many water molecules are in 36 grams of water?
15. Define “heterogeneous” and “homogeneous” mixtures.
16. What is the net electric charge of an atom?
17. What is atomic mass unit?
18. A carbon atom has six proton, six neutrons, and six electrons. What is the mass of a
carbon atom in atomic mass unit?
19. What would be different in question 3, if a different isotope of carbon atom is given?
20. Approximately how many elements are listed in the periodic table? How many can be
found in nature? What is the reason for the difference?
21. How many electrons, protons, and neutrons does an element given as X have?
22. What force holds the nucleons of an atom together?
23. How are the nuclear fusion and nuclear fission different?
24. What is the particle “x” in a nuclear reaction given as W + Y Z+ x
50 1 51
22 1 22.
25. What is the half life of a radioactive sample, if3/4of its nuclei decay in 2 years?
26. How many of the nuclei of a radioactive sample containing 2048nuclei decay in 3 years,
if its half life is given to be 6 months?
27. What are the nuclear radiations (name them)?
28. What is the difference between Uranium – 235 and Uranium – 238? Which one is more
desirable? What percentage of naturally occurring Uranium is Uranium-235?
29. How is energy created in mass conversion?
30. How does spectroscopy help to identify an element?
31. As you move away from the nucleolus of an atom, what happens to the number of
electrons in the electronic orbits?
32. How do you compare the size of an atom to the size of its nucleus (make numerical
comparison)?
33. What happens when an electron in an atom makes transition between two orbits?
34. What is the outcome of neutron decay?
35. What isotope is used for radioactive dating of previously lived entity?
