Content Benchmark P.12.A.9
Students know the number of electrons in an atom determines whether the atom is electrically neutral or an ion. I/S
Sample Test Questions
1 st Item Specification: Calculate the number of protons and electrons to determine the electrical charge of an atom.
Depth of Knowledge Level 1
1.
A sodium ion has 11 protons, 12, neutrons, and 10 electrons. How many electrons does the sodium ion need to gain to have a neutral charge?
A.
0
B.
1
C.
2
D.
11
2.
Analyze the table below showing information about four common elements.
Protons Neutrons Electrons Charge Element Symbol Mass number
Helium He
Sodium Na
Chlorine Cl
4
23
35
2
11
17
2
12
18
2
10
18
0
+1
-1
Carbon C 12 6 6 2 +?
Since the carbon ion has lost 4 electrons, what is the magnitude of the charge?
A.
4
B.
6
C.
10
D.
12
3.
Examine the information about four common elements in the table below.
Protons Neutrons Electrons Charge Element Symbol Mass number
Helium He
Lithium Li
Chlorine Cl
4
7
35
2
3
17
2
4
18
2
2
18
0
+1
-1
Nitrogen N 14 7 7 ? -3
How many electrons does the nitrogen atom contain?
A.
3
B.
4

C.
7
D.
10
Depth of Knowledge Level 2
4.
A sodium ion has 11 protons, 12, neutrons, and 10 electrons. For the sodium ion to become a neutral atom it will need to
A.
lose one electron.
B.
lose one neutron.
C.
gain one electron.
D.
gain one proton.
5.
Examine the model of ionic bonding below. The diagram shows sodium transferring an electron to chlorine to form sodium chloride or table salt. When sodium transfers an electron to chlorine both atoms become charged and are called ions.
Sodium (Na) Chlorine (Cl)
(From: http://www.visionlearning.com/library/module_viewer.php?mid=55 )
Choose the statement below that correctly identifies the positive and negative ions and the reason for those charges.
A.
Na is neutral because it lost one electron to Cl which became Cl
-
.
B.
Na becomes Na
+
because it lost one electron to Cl which became neutral.
C.
Na + because it lost one electron and Cl because it gained one electron.
D.
Na
-
because it lost one electron, and Cl
-
because it gained one electron.
6.
Examine the models of atoms below.
Atom A Atom B
Proton
Neutron
Electron

Which of the following correctly identifies the electrically neutral atom and the reason that it is neutral?
A.
Atom A is neutral because it has a greater number of neutrons than electrons.
B.
Atom A is neutral because it has a fewer number electrons than Atom B.
C.
Atom B is neutral because it has an equal number of neutrons and electrons.
D.
Atom B is neutral because at has an equal number of protons and electrons.
2 nd Calculate the magnitude and sign of the charge on an ion given the number of protons and electrons.
Depth of Knowledge Level 1
7.
An oxygen atom has 8 protons, 8 neutrons and 8 electrons. If the oxygen atom gains two electrons to form an oxygen ion what will be the magnitude and sign of the charge?
A.
-2
B.
+2
C.
-8
D.
+8
8.
Examine the information about four common elements on the table below.
Element Symbol Mass Protons Neutrons Electrons Charge
Helium He number
4 2 2 2 0
Sodium Na
Chlorine Cl
Oxygen O
23
35
16
11
17
8
12
18
8
10
18
10
+1
-1
-?
The oxygen ion has a negative charge. What is the magnitude of the charge on the oxygen ion?
A.
2
B.
8
C.
10
D.
16

Depth of Knowledge Level 2
9.
Examine the model of ionic bonding below. The diagram shows sodium giving and electron to chlorine to form sodium chloride or table salt. When sodium gives and electron to chlorine both atoms become charged and are called ions.
Sodium (Na) Chlorine (Cl)
(From http://www.visionlearning.com/library/module_viewer.php?mid=55 )
Choose the statement below that correctly identifies the magnitude and sign of the charge on each ion.
A.
Na and Cl
-
B.
Na
+
and Cl
-
C.
Na - and Cl +
D.
Na
- and Cl
10.
Examine the table below.
Element Symbol Mass
Number hydrogen H
Calcium Ca
1
40
Protons Neutrons Electrons Charge
1
20
0
20
1
18
0
+2
Fluorine
Iron
F
Fe
19
56
9
26
10
30
10
23
Oxygen O 16 8 8 10
Identify the charge and magnitude of the charge on the oxygen ion.
A.
0
B.
2
C.
+2
D.
-2
-1
+3
?

11.
Examine the models of the lithium atom and lithium ion below.
Lithium atom Lithium Ion
Proton
Neutron
Electron
Electron lost from lithium atom to form lithium ion.
Which of the following correctly identifies the amount and sign of the charge on the lithium ion?
A.
Li
-
B.
Li +
C.
Li
2+
D.
Li
2-
12.
Analyze the information about five common elements on the table below.
Element Symbol Mass number
Helium
Sodium
He
Na
4
23
Protons Neutrons Electrons Charge
2
11
2
12
2
10
0
+1
Chlorine
Silicon
Cl
Si
Aluminum Al
35
28
27
17
14
18
14
14
18
10
10
-1
+4
? ?
Which of the following correctly identifies the number of protons and the charge on the aluminum atom?
A.
10 protons, charge 0
B.
10 protons, charge +3
C.
13 protons, charge +3
D.
13 protons, charge -3

Content Benchmark P.12.A.9
Students know the number of electrons in an atom determines whether the atom is electrically neutral or an ion. I/S
Answers to Sample Test Questions
1.
B, DOK level 1
2.
A, DOK level 1
3.
D, DOK level 1
4.
C, DOK level 2
5.
C, DOK level 2
6.
D, DOK level 2
7.
A, DOK level 1
8.
A, DOK level 1
9.
B, DOK level 2
10.
D, DOK level 2
11.
B, DOK level 2
12.
C, DOK level 2