ATOMIC THEORY
Put the mass number after the symbol of the element.
 Carbon – 12.000000 amu
___________
 Carbon – 14.003242 amu ___________
 Lead – 209.98418 amu _____________
 Lead – 211.99188 amu _____________
1. Determine the following for the fluorine-19 atom.
a) # of protons ____
b) # of neutrons ____
d) atomic # ____
e) mass # ____
c) # of electrons ____
2. Repeat for bromine-80. a) # p+ ____ b) # no ____ c) # e- ____ d) atomic # ____ e) mass # ____
3. If an element has an atomic number of 34 and a mass number of 78, what is the
a) # of protons ____
b) # of neutrons ____
c) # of electrons ____
d) complete symbol
4. If an element has 91 protons and 140 neutrons, what is the
a) atomic # ____
b) mass # ____
c) # of electrons ____
d) complete symbol
5. If an element has 78 electrons and 117 neutrons what is the
a) atomic # ____
b) mass # ____
c) # of protons ____
d) complete symbol
MOLES
1. How many oxygen atoms are in the following?
a) CaCO3
b) Al2(SO4)3
2. How many total ions are in the following?
a) CaCl2
b) NaF
c) Al2S3
3. Perform the following mole-particle conversions.
a) How many ions of carbide (C4-) are there in 1.23 moles of carbide?
b) How many molecules of CO2 are in 4.56 moles of CO2?
c) How many atoms of iron are in 0.600 moles of iron?
d) How many moles are in 7.78 x 1024 formula units of MgCl2?
e) How many moles of water are 5.87 x 1022 molecules of water?
f) How many moles of aluminum are 1.2 x 1024 atoms of aluminum?
4. Calculate the number of particles (atoms, ions, formula units or molecules) in each of the following.
a) 3.4 moles Na2S
b) 0.0020 moles Zn
c) 1.77 x 10-11 moles C
d) 92.35 moles O2
Atomic Theory, Moles and Nuclear Chemistry – page 1
5. Calculate the number of moles in each of the following.
a) 3.4 x 1024 molecules HCl
b) 8.7 x 1021 atoms Zn
18
+3
c) 1.77 x 10 ions Al
d) 2.66 x 1026 atoms Cu
6. Calculate the molar mass of the each of the following elements.
a) sulfur (S)
b) chromium (Cr)
c) bromine (Br)
7. Calculate the molar mass of each of the following compounds.
a) Na2S
b) N2O4
c) C6H12O6
d) Ca(NO3)2
8. Perform the following mass-mole conversions.
a) How many moles of magnesium are in 56.3 g of Mg?
b) How many moles is 5.69 g of NaOH?
c) How many grams of sodium chloride are in 3.45 moles of NaCl?
d) How many moles is 4.8 g of CO2?
e) How many grams is 9.87 moles of H2O?
9. Perform the following mass-particle conversions.
a) How many atoms of lithium are in 1.00 g of Li?
b) How many formula units of sodium oxide are in 42.0 g of Na2O?
c) How much would 3.45 x 1022 atoms of uranium (U) weigh?
d) How many molecules are in 6.8 g of CH4?
e) How much do 49.0 molecules of C6H12O6 weigh?
10. Perform the following volume conversions.
a) What is the volume of 4.59 mole of CO2 gas at STP?
b) How many moles is 5.67 L of O2 at STP?
c) What is the volume of 8.8 g of CH4 gas at STP?
d) How many grams is 16.2 L of O2 at STP?
11. Calculate the number of liters in each of the following.
a) 3.10 x 1024 molecules Cl2
b) 8.7 moles Ne
18
c) 2.77 x 10 atoms He
d) 266 grams SO2
NUCLEAR CHEMISTRY
1. When beryllium-9 is bombarded with alpha particles (helium nuclei), a neutron is produced. The
balanced nuclear reaction is given as: ________________________________________________
2. When nitrogen-14 is bombarded with a neutron, a proton is produced. The balanced nuclear equation
can be written as: _________________________________________________________
3. Thorium-230 undergoes alpha decay: ________________________________________________
4. Uranium-234 undergoes alpha decay: ________________________________________________
5. Cobalt-50 undergoes beta decay: ____________________________________________________
Atomic Theory, Moles and Nuclear Chemistry – page 2
6. What element is formed when iron-60 undergoes beta decay? Give the atomic number and mass number
of the element. ____________
7. Write a balanced nuclear equation for the alpha decay of the following radioisotope, uranium-235.
________________________________________________________________________________
8. Nitrogen-12 decays into a positron and another element. Write the balanced nuclear equation.
________________________________________________________________________________
9. Uranium-238 is bombarded with a neutron. One product forms along with gamma radiation. Write the
balanced nuclear equation.
________________________________________________________________________________
10. Nitrogen-14 is bombarded with deuterium (hydrogen-2). One product forms along with an alpha
particle. Write the balanced nuclear equation.
___________________________________________________________________________
11. Iron-59 is used in medicine to diagnose blood
circulation disorders. The half-life of iron-59 is
44.5 days. How much of a 2.000-mg sample will
remain after 133.5 days?
12. Cobalt-60 has a half-life of 5.27 years. How much of a
10.0 g sample will remain after 21.08 years?
time
0
Half-life
Half-life x 2
Half-life x 3
Half-life x 4
amount
Initial amount
Initial amount ÷ 2
Initial amount ÷ 4
Initial amount ÷ 8
Initial amount ÷ 16
13. If 100.0 g of carbon-14 decays until only 25.0 g of carbon is left after 11,460 yr, what is the half-life of
carbon-14?
14. What is the half-life in days of an isotope if 125 grams of a 1000 gram sample remain after 15 days?
15. What is the half-life in years of an isotope if 1 gram of a 16 gram sample remains after 16 years?
16. The half-life of hafnium-156 is 0.025 s. How long will it take a 560 g sample to decay to one-fourth its
original mass?
17. Chromium-48 has a short half-life of 21.6 h. How long will it take 360.00 g of chromium-48 to decay
to 11.25 g?
18. If the half-life of uranium-235 is 7.04 x 108 yr and 12.5 g of uranium-235 remain after 28.2 x 108 yr,
how much of the radioactive isotope was in the original sample?
19. Carbon-14 has a half-life of 5730 years. How much of a 250. g sample will remain after 5730 years?
20. What is the main difference between nuclear fusion and nuclear fission? ________________________
______________________________________________________________________________________
Atomic Theory, Moles and Nuclear Chemistry – page 3