1. Unit 2 Review

2. TRUE or FALSE
Salt (NaCl) is a pure substance and an element.

3. ANSWER False… pure substance and compound.
Two elements combined = compound

4. Which state of matter would take the shape of it’s container and has a fixed/definite volume?

5. ANSWER
Liquid

6. A popsicle melting on the sidewalk is an example of what type of change?

7. ANSWER
Physical…all phase changes (solid  liquid  gas) are physical changes.

8. “A shiny piece of steel rusted from sitting out in the rain.”
Which part of this statement represents a physical property? Which part represents a chemical property?

9. ANSWER “A shiny piece of steel rusted from sitting out in the rain.”
“SHINY” is physical, describing what it looks like
“RUSTING” is chemical, because rust has a different composition than steel.

10. Matter changing from its liquid state to its gaseous state is called ______.

11. ANSWER
Vaporization
Boiling
Evaporation

12. What is an ion?

13. ANSWER An atom with a positive or negative charge.
An atom that has lost or gained electrons.

14. If at ion has a positive charge, did it GAIN electrons or LOSE electrons?

15. ANSWER
LOSE electrons so that the there are now more positive protons than there are negative electrons.

16. How many neutrons does Carbon-14 have?

17. ANSWER
14 is the mass number of that particular isotope of Carbon and the atomic number of Carbon is 6, so
14-6= 8 neutrons.

18. TRUE or FALSE
To get an isotope, you fluctuate the number of electrons.

19. ANSWER
FALSE. You would fluctuate the number of neutrons to change the mass.

20. Who discovered protons? LAST NAME, HOW?

21. ANSWER
Ernest Rutherford by shooting alpha particles (positive particles) at a piece of foil. The alpha particles deflected, which showed they were hitting something else that was positive (protons).

22. Who came up with the first atomic theory?

23. ANSWER
John Dalton

24. Who discovered electrons and how? LAST NAME

25. ANSWER
JJ Thomson- cathode ray tube showed electrons are emitted. Negative side of magnet repelled (or positive side attracted) so proved they were negative.

26. What part of the atom gives it it’s identity?

27. ANSWER
Protons

28. Would spaghetti be a pure substance or a mixture?

29. ANSWER
Mixture (heterogeneous)

30. What are the 3 particles of the atom and their respective charges?

31. ANSWER
Proton +
Neutron (neutral)
Electron -

32. Why isn’t the mass of strontium-92 on the periodic table reported as 92?

33. ANSWER
The periodic table shows average atomic masses of all isotopes present

34. How many electrons fit on energy level 1, 2,& 3?

35. ANSWER
1st holds 2
2nd holds 8
3rd holds 8

36. Who created the atom model where electrons are found on energy levels?

37. ANSWER
Niels Bohr

38. Draw the Bohr diagram for phosphorus.

39. ANSWER
15 P
16 N
15 E

40. Write the following info in isotopic notation
Protons- 26
Neutrons- 31
Electrons- 23

41. ANSWER
57Fe3+ 26

42. Atomic Number
Mass Number
Neutrons
Electrons

43. ANSWER
Atomic Number- 16
Mass Number- 33
Neutrons- 17
Electrons -18

44. Who discovered the neutron?

45. ANSWER
James Chadwick

46. Protons-20
Electrons-20
Neutrons-22
Isotope name?

47. ANSWER
Calcium-42

48. Protons-20
Electrons-20
Neutrons-22
Give the correct notation.

49. ANSWER

50. What is the name of the element if the only information you have is there are 35 protons?

51. ANSWER
Bromine

52. List techniques for physically separating a mixture (think about our lab)

53. ANSWER
Filtering
Using a magnet
Boiling
Dissolving