1. Match the following people with their contributions to atomic theory?
___1. Law of Conservation of Mass A. Bohr
___2. The discovery of the electron B. Rutheford
___3. Law of Definite Proportions C. Proust
___4. The discovery of the nucleus D. Thomson
___5. The planetary Model of the atom E. Lavoisier

2. Match the following people with their contributions to atomic theory?
_E_1. Law of Conservation of Mass A. Bohr
_D_2. The discovery of the electron B. Rutherford
_C_3. Law of Definite Proportions C. Proust
_B_4. The discovery of the nucleus D. Thomson
_A_5. The planetary Model of the atom E. Lavoisier

3. According to the Law of Conservation of Mass, what is the missing mass of the compound in the equation below?
𝐶𝑎 (𝑂𝐻) HCl → 𝐶𝑎 𝐶𝑙 𝐻 2 O
18g g = g + ___g

4. According to the Law of Conservation of Mass, what is the missing mass of the compound in the equation below?
𝐶𝑎 (𝑂𝐻) HCl → 𝐶𝑎 𝐶𝑙 𝐻 2 O
18g g = g + _8.8_g
In a chemical equation, mass can neither be created or destroyed. Therefore the total mass on one side of a chemical equation must equal the mass on the other side.

5. What is the name of the Law that explains why the two molecules below are different?
CO and CO2

6. What is the name of the Law that explains why the two molecules below are different?
CO and CO2
The Law of Definite Proportions
This law states that for every compound, there is a definite proportion of atoms in the compound.
Although CO and CO2 both consist of carbon and oxygen, the ratio of those two atoms in each compound determines the identity and properties of the each compound.

7. In the diagram below, would the cathode ray be attracted or deflected from the magnet above?+ + -

8. In the diagram below, would the cathode ray be attracted or deflected from the magnet above?+ + -
Because cathode rays are made of electrons which are negatively charged, cathode rays will be attracted to the positive end of a magnet.

9. What was the name of Thomson’s model of the atom and what did it consist of?

10. What was the name of Thomson’s model of the atom and what did it consist of?
The “Plum Pudding” model

11. What was the name of Rutherford’s model of the atom and what did it consist of?

12. What was the name of Rutherford’s model of the atom and what did it consist of?
The “Nuclear” Model
Electrons in orbit

13. How did Rutherford discover the nucleus of the atom?

14. How did Rutherford discover the nucleus of the atom?
He shot positively charged alpha particles at a sheet of gold foil and most of the time the particles were observed to go right through the foil. Sometimes, the particles’ path was bent and only about 0.01% of the time, particles bounce back. From these observations Rutherford concluded that:
The atom was made of mostly empty space.
The center of the atom was dense (compact) and positively charged.

15. Dalton proposed that atoms of one element were identical, but different from atoms of another element. Why was he wrong? Explain.

16. Dalton proposed that atoms of one element were identical, but different from atoms of another element. Why was he wrong? Explain.
It is true that atoms of one element are different from atoms of another element. However, atoms of the same element can also be different by the number of neutrons that they contain. For example, all carbon atoms are not the same. There are 3 naturally occurring ISOTOPES of carbon: carbon-12, carbon-13 and carbon-14. Each contains the same number of protons and electrons but a different number of neutrons.

17. Fill in the table Element Protons Neutrons Electrons Mass number
Isotope 28 60

18. Fill in the table Nickel 28 32 60 Ni-60 Element Protons Neutrons
Electrons
Mass number
Isotope
Nickel 28 32 60
Ni-60

19. Why is the mass of an atom roughly equal to the mass of only the protons and neutrons in the atom?

20. Why is the mass of an atom roughly equal to the mass of only the protons and neutrons in the atom?
The mass of an electron is only about 1/2000 the mass of either a proton or neutron and therefore contributes very little to the mass of the atom.

21. Determine the atomic mass of potassium using the following data.
Isotope
Mass
% Abundance
K-39
93.20
K-40
0.012
K-41
6.73

22. Determine the atomic mass of potassium using the following data.
Isotope
Mass
% Abundance
(changed to abundance)
Multiply Mass times abundance
K-39
0.9320
K-40
K-41
0.0673
Atomic Mass of Potassium = *
* Add the numbers in the last column to get the mass of the element

23. The atomic mass of Iridium is 192.22
Which isotope contributes more to the mass of Iridium, Ir-191 or Ir-193?
Ir-191 has a mass of and Ir-193 has a mass of
The atomic mass of Iridium is
Ir(191) Ir(193)

24. The atomic mass of Iridium is 192.22
Which isotope contributes more to the mass of Iridium, Ir-191 or Ir-193?
Ir-191 has a mass of and Ir-193 has a mass of
The atomic mass of Iridium is
The atomic mass of iridium is closest to the mass of Ir In fact, Ir-193 makes up about 67% of all iridium atoms whereas only 33% of iridium atoms are of the Ir-191 type.

25. How many atomic orbitals can be found in each of the following sublevels?
s p d f

26. How many atomic orbitals can be found in each of the following sublevels?
s p d f
Each orbital holds 2 electrons. So in any s sublevel there are 2 electrons, 6 electrons in a p sublevel, 10 electrons in a d sublevel and 14 electrons in a f sublevel.

27. What is the electron configuration of arsenic?

28. What is the electron configuration of arsenic?
1s22s22p63s23p64s23d104p3 or [Ar] 4s23d104p3
The first configuration is written in long-hand notation. The second configuration is written using a noble gas to account for all of the electrons through the 3p. Noble gases can be used in this way because their configurations are very stable.

29. How many valence electrons does arsenic have?

30. How many valence electrons does arsenic have?
Valence electrons are the outermost electrons in an atom. The number of valence electrons can be determined two ways for most atoms.
Look at the electron configuration and find all of the electrons that exist at the highest energy level. Those are the valence electrons.
[Ar] 4s23d104p3 = 5 valence electrons
2. Find the column number that the element is in. For elements that are in the last 6 columns of the table, only look at the ones digit in the column number. Arsenic is in column 15, so it has 5 valence electrons.

31. What information does a Lewis dot structure contain
What information does a Lewis dot structure contain? What is the structure for arsenic?

32. What information does a Lewis dot structure contain
What information does a Lewis dot structure contain? What is the structure for arsenic?
The Lewis dot structure contains the symbol for the element and its valence electrons. There can only be a maximum of 8 valence electrons for any atom, 2 on each side of the element symbol.
Make sure to only pair up electrons for atoms that have more than 4 valence electrons.

33. Which of the following graphs shows the relationship between wavelength and frequency? Between energy and frequency? A B

34. Which of the following graphs shows the relationship between wavelength and frequency? Between energy and frequency? A
In A, when energy and frequency are plotted on a graph, the variables will change in the same direction which will give a positive slope. B
In B, when wavelength and frequency are plotted on a graph, the variables will change in the opposite direction which will give a negative slope.

35. Which wave has the shortest wavelength, the highest frequency and the highest energy?B C

36. Which wave has the shortest wavelength, the highest frequency and the highest energy?B C
Wave C has all of those characteristics

37. How is an atomic emission spectrum different from the electromagnetic spectrum?

38. How is a continuous spectrum different from an atomic emission spectrum?
The continuous spectrum contains all wavelengths and frequencies of visible light.
The atomic emission spectrum corresponds to the wavelength and frequencies of light given off by the electrons of specific atoms when they become excited.

39. What is the frequency of a wave that has a wavelength of 3 x 10-10m
What is the frequency of a wave that has a wavelength of 3 x 10-10m? What is the energy of the same wave?

40. What is the frequency of a wave that has a wavelength of 3. 0 x 10-10m
What is the frequency of a wave that has a wavelength of 3.0 x 10-10m? c=ln n=c/l 𝑣= 3.0 𝑥 𝑥 10 −10 = 1.0 x 1012/s What is the energy of the same wave? E=hn E=6.626 x 10-34J.s x 1.0 x 1012/s = 6.626x 10-22J