WorksheetsAtomic Structure Review Assignment
Total questions: 18
Worksheet time: 1hrs 15mins
Which part of the atom contains most of the mass?
Electrons
Nucleus
Protons
Neutrons
Determine the atomic number, mass number, number of protons, neutrons, and electrons for a neutral atom of potassium-39.
Atomic # 19
Mass # 39
Protons 19
Neutrons 20
Electrons 19
Atomic # 19
Mass # 39.098
Protons 19
Neutrons 19
Electrons 19
Atomic # 39
Mass # 19
Protons 39
Neutrons 19
Electrons 39
Atomic # 19
Mass # 39.098
Protons 19
Neutrons 20
Electrons 19
Isotopes have the same number of ____, but different number of ____.
neutrons; protons
protons; electrons
protons + electrons; neutrons
electrons; protons
Naturally occurring chlorine that is put in pools has an average atomic mass of 35.46 amu. The two isotopes that exist are chlorine-35 and chlorine-37. Which isotope is more abundant?
Chlorine-35
Chlorine-37
In a neutral atom what two subatomic particles are equal?
Neutrons + Protons
Electrons + Neutrons
Protons + Electrons
How many neutrons are in carbon-14?
6
8
7
14
What steps do you take when calculating the average atomic mass of an element?
- Add up the atomic masses of each isotope
- Divide by the number of isotopes there are
- Multiply the atomic mass of each isotope by its percent abundance divided by 100
- Sum the products
- Multiply the atomic mass of each isotope by its percent abundance divided by 100
- Sum the products
- Divide by the number of isotopes there are
- Multiply the atomic mass of each isotope by the percent abundance
- Sum the products
There are two naturally occuring isotopes of lithium, lithium-7 and lithium-6. If the average atomic mass is 6.941 which isotope is more abundant?
Neither, same abundance
Lithium-6
Lithium-7
The table below gives the atomic mass and the abundance of the two naturally occurring isotopes of bromine.
Which numerical setup can be used to calculate the atomic mass of the element bromine?
(78.92 u)(50.69) + (80.92 u)(49.31)
(78.92 u)(49.31) + (80.92 u)(50.69)
(78.92 u)(0.5069) + (80.92 u)(0.4931)
(78.92 u)(0.4931) + (80.92 u)(0.5069)
The average isotopic mass of chlorine is 35.5. Which mixture of isotopes (shown as percents) produces this average mass?
50% 12C and 50% 13C
50% 35Cl and 50% 37Cl
75% 12C and 25% 13C
75% 35Cl and 25% 37Cl
If 75.0% of the isotopes of an element have a mass of 35.0 amu and 25.0% of the isotopes have a mass of 37.0 amu, what is the atomic mass of the element?
35.0 amu
36.0 amu
35.5 amu
37.0 amu
Carbon-14 (atomic number 6), the radioactive nuclide used in dating fossils, has
6 neutrons.
8 neutrons.
10 neutrons.
14 neutrons.
What does the number 84 in krypton-84 represent?
the atomic number
the mass number
the sum of the protons and electrons
twice the number of protons
What unit is used to measure weighted atomic mass?
amu
gram
angstrom
nanogram
The number of _________ present in an atom determines whether or not that atom is radioactive.
protons
neutrons
electrons
nuclei
Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the isotope with a mass number of 22.0 is 65.0% abundant; the isotope with a mass number of 24.0 is 35.0% abundant. What is the average atomic mass for element Z?
19.9 amu
22.7 amu
23 amu
23.3 amu
Calculate the atomic mass of silicon. The three silicon isotopes have atomic mass and relative abundances of 27.9769 amu (92.2297%), 28.9765 amu (4.6832%) and 29.9738 amu (3.0872%).
28.0853 amu
25166.4483 amu
2808.5389 amu
28.0546 amu
Gallium has two naturally occurring isotopes. The mass of gallium-69 is 68.9256 amu and it is 60.108% abundant. The mass of gallium-71 is 70.9247 amu and it is 39.892% abundant. Calculate the atomic mass of gallium.
4958.8597 amu
6972.3081 amu
70.0928 amu
69.7231 amu
