Chemistry Worksheet - Practice Exam With Answer Key
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1
2
3Unit 4 Practice Exam
Period:
Name:
ANSWER KEY
1.
What subatomic particles are found in the nucleus?
protons and neutrons
2.
Give the name and charge for each of the three primary subatomic particles:
a.
Electron: -1 charge
b.
neutron: no charge
c.
proton: +1 charge
3.
How do you find the mass number of a certain isotope?
Add the number of protons and
neutrons of the isotope together (most common is the rounded off atomic mass)
4.
What is the difference between mass number and atomic mass?
Atomic mass is the weighted
average of all of the masses of all the different isotopes of an atom, while mass number is just
the number of protons and neutrons for a particular isotope
5.
What happens if somehow a proton were added to a nucleus of an atom?
The type of
atom changes to the next atomic number (if no electrons were added it would be a +1 cation).
It’s just a different
6.
What happens if somehow a neutron were added to a nucleus of an atom?
isotope of that element, basically same physical properties, just more massive
7.
Where is most of the mass of an atom located?
Inside the nucleus
8.
How much of the atom's volume is found in the nucleus?
Almost none of it
9.
What particle is mostly responsible for an atom's physical properties?
protons
10. What particle is mostly responsible for an atom's chemical properties?
electrons
11. What "glues" the nucleus together?
neutrons
12. What do you call atoms with the same number of protons, but different numbers of neutrons?
isotopes of the atom
13. What are the most common isotopes of the following?
a. Carbon
Carbon-12
c. Lead
Lead-207
b. Zinc
Zinc-65
d. Chlorine
Chlorine-35
14.
Write the name of the Uranium isotope with 147 neutrons.
Uranium-239 (U has 92 protons,
92 + 147 = mass number = 239, this is not the most common isotope)
15.
Write the number of protons, Neutrons, and electrons, and isotope name for the following
neutral most common isotopes of the following:
+
-
a. Zr
p
= 40, n = 51, e
= 40, zirconium-91
+
-
b. Na
p
= 11, n = 12, e
= 11, sodium-23
+
-
c. H
p
= 1, n = 0, e
= 1, hydrogen-1
+
-
d. Mg
p
= 12, n = 12, e
= 12, Magnesium-24
16.
A neutral atom has 19 electrons. What is the atom?
Potassium (because K has 19 protons
to cancel out the 19 electrons)
17.
An atom has 15 protons, 18 electrons, and 16 neutrons. What is the atom, what is its charge,
and what is its mass number?
Phosphorus with a -3 charge and mass number of 31
18.
A lithium atom with a total of 2 electrons is called a what?
+1 lithium cation
19.
What does the row number on the periodic table tell you?
Number of energy levels
occupiedin the ground state
20.
What does the column numbers (on the A groups) of the period table tell you?
The number
of electrons in the highest energy level (that are available for bonding) – valence electrons
21.
Draw Bohr diagrams of the following:
a. The most common
b. A +2 Cation of
c. A -2 Anion of
Oxygen atom.
Calcium.
Oxygen.
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