2. Atoms Atomic Mass/Number Ions/Charges of Molecules Isotopes/Perc ent Abundance 10 20 30 40 50

3. Question 1 - 10 Define an atom. Define an atom.

4. Answer 1 – 10 The basic unit of a chemical element The basic unit of a chemical element

5. Question 1 - 20 Where is most of the mass of an atom located? Where is most of the mass of an atom located?

6. Answer 1 – 20 Nucleus Nucleus

7. Question 1 - 30 Using a cathode ray tube, JJ Thompson discovered what subatomic particle? Using a cathode ray tube, JJ Thompson discovered what subatomic particle?

8. Answer 1 – 30 Electrons Electrons

9. Question 1 - 40 An element contains atoms with the same number of what subatomic particle? An element contains atoms with the same number of what subatomic particle?

10. Answer 1 – 40 Protons Protons

11. Question 1 - 50 What is a molecule? What is a molecule?

12. Answer 1 – 50 Two or more atoms with a definite arrangement held together by chemical bonds. Two or more atoms with a definite arrangement held together by chemical bonds.

13. Question 2 - 10 The atomic number of an atom is equal to what? The atomic number of an atom is equal to what?

14. Answer 2 – 10 Protons Protons

15. Question 2 - 20 Calculate the atomic mass of Oxygen with 10 neutrons. Calculate the atomic mass of Oxygen with 10 neutrons.

16. Answer 2 – 20 18 18

17. Question 2 - 30 Element X has an atomic number of 15 and an atomic mass of 37. How many neutrons does element X have? Element X has an atomic number of 15 and an atomic mass of 37. How many neutrons does element X have?

18. Answer 2 – 30 22 22

19. Question 2 - 40 What is the unit used for measuring the mass of atoms. What is the unit used for measuring the mass of atoms.

20. Answer 2 – 40 Atomic mass units (amu) Atomic mass units (amu)

21. Question 2 - 50 What is the atomic number of Calcium? If Calcium has 24 neutrons, what is its atomic mass? What is the atomic number of Calcium? If Calcium has 24 neutrons, what is its atomic mass?

22. Answer 2 – 50 The atomic number is 20, and its mass is 44. The atomic number is 20, and its mass is 44.

23. Question 3 - 10 Define an ion. Define an ion.

24. Answer 3 – 10 An atom with a net positive or negative charge. An atom with a net positive or negative charge.

25. Question 3 - 20 What is the difference between anions and cations? What is the difference between anions and cations?

26. Answer 3 – 20 Anions have a negative charge and cations have a positive charge. Anions have a negative charge and cations have a positive charge.

27. Question 3 - 30 What two subatomic particles must be equal in order to create a neutral atom? What two subatomic particles must be equal in order to create a neutral atom?

28. Answer 3 – 30 Protons and Electrons Protons and Electrons

29. Question 3 - 40 How many electrons are in S -2 ? How many electrons are in S -2 ?

30. Answer 3 – 40 18 electrons 18 electrons

31. Question 3 - 50 Which atom has more electrons? Mg +1 or O -2 ? Which atom has more electrons? Mg +1 or O -2 ?

32. Answer 3 – 50 Mg +1 Mg +1

33. Question 4 - 10 Define isotope Define isotope

34. Answer 4 – 10 Atoms of the same element with different numbers of neutrons resulting in different atomic masses. Atoms of the same element with different numbers of neutrons resulting in different atomic masses.

35. Question 4 - 20 How many neutrons are in a Carbon isotope with a mass of 20? How many neutrons are in a Carbon isotope with a mass of 20?

36. Answer 4 – 20 8 neutrons 8 neutrons

37. Question 4 - 30 Calculate the average atomic mass of these two Nitrogen isotopes: 95% 14 N and 5% 15 N. Calculate the average atomic mass of these two Nitrogen isotopes: 95% 14 N and 5% 15 N.

38. Answer 4 – 30 14.05 amu 14.05 amu

39. Question 4 - 40 Calculate the average atomic mass of these three isotopes of Oxygen: 78% 16 O, 8% 17 O, 14% 18 O. Calculate the average atomic mass of these three isotopes of Oxygen: 78% 16 O, 8% 17 O, 14% 18 O.

40. Answer 4 – 40 16.36 amu 16.36 amu

41. Question 4 - 50 There are three isotopes of Silicon: 84% 28 Si, 10% 29 Si, 6% 30 Si. A: How many neutrons does each isotope have? B: What is the average atomic mass? (Silicon has an atomic number of 14) There are three isotopes of Silicon: 84% 28 Si, 10% 29 Si, 6% 30 Si. A: How many neutrons does each isotope have? B: What is the average atomic mass? (Silicon has an atomic number of 14)

42. Answer 4 – 50 A: 1) 14 2) 15 3) 16 A: 1) 14 2) 15 3) 16 B: 28.22 amu B: 28.22 amu