Download Dr. Harris Chemistry 105 Practice Exam 1 Isotope Atomic Number

Dr. Harris
Chemistry 105
Practice Exam 1
1. Fill in the table below. Include ionic charges
Isotope
Atomic Number
Neutrons
Mass Number
Electrons
122
54
51
48 4+
22𝑇𝑖
117
𝑃𝑡
74
2. Name the following
a) SO3
b) WO3
c) Pt(CO3)2
d. HCl
e. TeH2
f. Hg2SO3
3. What is the electron configuration of the 2nd excited state of S?
4. Using the Pauli Exclusion Principle, explain why an s-orbital can hold a maximum of 2 electrons?
5. Balance the following: C6H14 (l) + O2 (g)
CO2 (g) + H2O (g)
6. Answer the following.
a.) Using electron configurations, show the formation of MgO.
b.) Why does this reaction proceed? (3)
c.) Refer to the table of ionization energies in Ch 4 of your book, as
well as the table of electron affinities shown on the right. Assume
the radii of Mg2+ and O2- to be 130 pm and 200 pm, respectively.
Calculate the energy change associated with the formation of MgO .
7. Which ion has the largest radius?
a) Pt4+
b) Ir6+
c) O2d) Sn2+
8. The number of protons in an atom determines its:
a)
reactivity
b)
chemical identity
c)
solubility
d)
phase
9. Which of the following sets of quantum numbers does NOT represent a possible ground state
electron of Zr:
a)
5, 0, 0, ½
b)
5, 1, 1, ½
c)
4, 0, 0, - ½
d)
2, 1, -1, - ½
e)
3, 2, -2, ½
10. Explain how and why atoms emit light.
11. Why does the Bohr model fail for atoms with more than one electron?
12. A certain element, X, has 3 isotopes (49X, 50X, and 51X). The isotope masses are 49.122 amu, 50.456
amu, and 51.246 amu. Analysis confirms that 3.00% of all X is 51X. Given that the average mass of X is
50.000, determine the percent abundances of the other isotopes.
13. A sphere of gold has a diameter of 3 inches. Given that the mass of this sphere is 4469 g, calculate
the density of gold in g/cm3 to the correct number of significant figures.
14. A laser emits 200mJ of energy per hour. Given that the wavelength of the photons in the beam is
300 nm, and assuming that the emission rate is constant, how many photons are emitted per minute?
15. A photon with some energy Ep strikes a metal surface. An electron is ejected with a velocity of
5.00 Mm/s. The threshold frequency of the metal is 6.30 x 1013 s-1. What is the wavelength of the
photon, in nm? Significant figures count.
16.
What is an orbital?
17.
Why do atoms exhibit discontinuous (line) spectra when they emit light? Why can’t an atom
emit any wavelength of light?
18. Refer to the activity series in chapter 10. For the single replacement reactions below, write the half
reactions. Label the reducing and oxidizing agents. Show the net ionic equation. If no reaction occurs,
write “no reaction”.
a.) Titanium (IV) perchlorate (aq) + Lithium (s) 
b.) Magnesium (s) + Sulfuric acid (aq) 
c.) Aluminum nitrate (aq) + Potassium (s) 
19. Provide an acceptable set of quantum numbers for a valence electron on a Boron atom.
20. If you have not done so, answer the BONUS question on your last quiz.
Equations
𝐸𝑛 = 𝑛ℎ𝑣
𝑣𝜆 = 𝑐
𝜌 = 𝑚𝑎𝑠𝑠/𝑣𝑜𝑙𝑢𝑚𝑒
𝐸𝑘 = 𝐸𝑝ℎ𝑜𝑡𝑜𝑛 − 𝐸𝑡ℎ𝑟𝑒𝑠ℎ𝑜𝑙𝑑 = ℎ𝑣𝑝 − ℎ𝑣𝑇
𝐹𝑜𝑟 𝑎𝑛 𝑒𝑙𝑒𝑐𝑡𝑜𝑛 𝑖𝑛 𝑚𝑜𝑡𝑖𝑜𝑛: 𝐸𝑘 =
̅̅̅2̅
𝑚𝑒 𝑉
2
h = 6.626 x 10-34 Js
c = 3 x 108 ms-1
me = 9.109 x 10-31 kg
Volume of a sphere =
𝐸𝑐 = 𝑘
𝑄1 𝑄2
𝑑
4
𝜋𝑟 3
3
where r is the radius
where k = 231 aJ•pm, d = nuclear separation distance, Q = charge
Conversions:
1 in = 2.54 cm