Unit 3 – Atomic Structure and Periodicity Evaluation
- Calculate the wavelength (in nm) of the red light emitted by a barcode scanner that has a frequency of
4.62 × 1014 s–1.
- A laser dazzles the audience in a rock concert by emitting green light with a wavelength of 515 nm. Calculate the frequency of the light.
- A nitrogen gas laser pulse with a wavelength of 337 nm contains 3.83 mJ of energy. How many photons does it contain?
4. Arrange the three types of electromagnetic radiation—visible light, X-rays, and microwaves—in order of increasing
a. wavelength. b. frequency. c. energy per photon.
- What are the quantum numbers and names (for example, 2s, 2p) of the orbitals in the n = 4 principal level? How many n = 4 orbitals exist?
- These sets of quantum numbers are each supposed to specify an orbital. One set, however, is erroneous. Which one and why?
a. n = 3; l = 0; ml = 0 b. n = 2; l = 1; ml= –1
c. n = 1; l = 0; ml = 0 d. n = 4; l = 1; ml = –2
- Determine the wavelength of light emitted when an electron in a hydrogen atom makes a transition from an orbital in n = 6 to an orbital in n = 5.
- Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in which n = 2 to an orbital in which n =
- Two samples of carbon dioxide are decomposed into their constituent elements. One sample produces 25.6 g of oxygen and 9.60 g of carbon, and the other produces 21.6 g of oxygen and 8.10 g of carbon. Show that these results are consistent with the law of definite proportions.
10. Nitrogen forms several compounds with oxygen, including nitrogen dioxide and dinitrogen monoxide. Nitrogen dioxide contains 2.28 g oxygen to every 1.00 g nitrogen, while dinitrogen monoxide contains 0.570 g oxygen to every 1.00 g nitrogen. Show that these results are consistent with the law of multiple proportions.
11. a. What are the atomic number (Z), mass number (A), and symbol of the chlorine isotope with 18 neutrons?
b. How many protons, electrons, and neutrons are present in an atom of Cr-24?
c. What are the atomic number, mass number, and symbol for the carbon isotope with seven neutrons?
12. Write electron configurations for each element.
a. Mg b. P c. Br d. Al
13. Write electron configurations for each element.
a. Cl b. Si c. Sr d. O
14. Write the orbital diagram for sulfur and determine the number of unpaired electrons.
15. Write the orbital diagram for Ar and determine the number of unpaired electrons.
16. Write the electron configuration for Ge. Identify the valence electrons and the core electrons.
17. On the basis of periodic trends, choose the larger atom in each pair (if possible):
a. Sn or I b. Ge or Po c. Cr or W d. F or Se
18. Write the electron configuration and orbital diagram for each ion and determine whether each is diamagnetic or
paramagnetic.
a. Al3+ b. S2– c. Fe3+
19. Choose the larger atom or ion from each pair.
a. S or S2– b. Ca or Ca2+ c. Br – or Kr
20. On the basis of periodic trends, determine which element in each pair has the higher first ionization energy (if possible).
a. Al or S b. As or Sb c. N or Si d. O or Cl
21. What are the atomic number (Z), mass number (A), and symbol of the chorine isotope with 18 neutrons?
22. How many protons, electrons and neutrons are present in an atom of 52 Cr?
23. How many protons and neutrons are present in an atom of 39 K?
24. Copper has two naturally occurring isotpoes: Cu-63 with a mass of 62. 9291 amu and a natural abundance of 69.71%. and Cu-65 with a mass of 64.9278 amu and a natural abundance of 30.83%. Calculate the atomic mass of Cu.
25. The 3 particles of the atom are:
a. ________________________ b. ________________________ c. ________________________
Their respective charges are:
a. ________________________
b. ________________________
c. ________________________
26. The number of protons in one atom of an element determines the atom’s ____________________, and the number of electrons determines the _________________________ of the element.
27. The atomic number tells you the number of ___________________________ in one atom of an element. It also tells you the number of __________________________ in a neutral atom of that element. The atomic number gives the “identity” of an element as well as its location on the periodic table. No two different elements will have the ____________________ atomic number.
28. The ______________________ of an element is the average mass of an element’s naturally occurring atom, or isotopes, taking into account the ____________________ of each isotope.
29. The _______________________ of an element is the total number of protons and neutrons in the ___________________ of the atom.
30. The mass number is used to calculate the number of ______________________ in one atom of an element. In order to calculate the number of neutrons you must subtract the ______________________ from the ___________________.
31. Given the elements name and its mass number give the complete isotopic symbol and the number of neutrons for the following:
Lithium-6 _____________________________
Iron-58 _____________________________
Oxygen-17 _____________________________
Krypton-78 _____________________________
Bromine-79 _____________________________
Copper-65 _____________________________
Mercury-200 _____________________________
Helium-3 _____________________________
32. Give the element symbol of and the number of electrons in a neutral atom of:
Uranium _____________________________
Boron _____________________________
Chlorine _____________________________
Iodine _____________________________
Xenon _____________________________
33. Name the element which has the following numbers of particles:
a. 26 electrons, 26 protons _________________________
b. 53 protons, 74 neutrons __________________________
c. 2 electrons (neutral atoms) ____________________________
d. 20 protons _____________________________
e. 86 electrons, 125 neutrons, 82 protons ____________________________
f. 0 neutrons _______________________________
34. If you know ONLY the following information can you ALWAYS determine what the element is? (Yes/No)
a. Number of protons ____________________________
b. Number of neutrons ___________________________
c. Number of electrons in a neutral atom ___________________________
d. Number of electrons _________________________
35. Fill in the missing items in the table below.
Complete the table. Use a periodic table where needed. There is enough information given for each element to determine all missing numbers.
| Symbol | Atomic Number(Z) | Mass Number(A) | Number of Protons | Number of Electrons | Number of Neutrons |
|
23Na |
|||||
|
K |
40 |
19 |
|||
|
|
38 |
38 |
52 |
||
|
F |
10 |
||||
|
|
20 |
41 |
18 |
||
|
|
50 |
50 |
72 |
||
|
131I |
|||||
|
26Mg |
|||||
|
|
109 |
47 |
46 |
||
|
|
1 |
2 |
1 |
||
|
36S |
|||||
|
|
26 |
23 |
32 |
||
|
27Al |
|||||
|
|
2 |
4 |
2 |
||
|
Cr |
53 |
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