Page 85 - Chemistry eBook

The atomic number and corresponding atomic radius of the Period 3 elements are
Base your answers to questions 55 through 58 on the information below.
The atomic number and corresponding atomic radius of the Period 3 elements are 15 109
shown in the data table below.
Data Table
shown in the data table below.
Data Table
Atomic Radius (pm)
11 160.
12 140.
Atomic Number
Sample Regents Questions
16 104 55 and 56 17 100.
18 101
55 On the grid in your answer booklet, mark an appropriate scale on the axis labeled “Atomic Radius (pm).” [1]
56 On the grid in your answer booklet, plot the data from the data table. Circle and connect the points. [1]
57 Statethegeneralrelationshipbetweentheatomicnumberandtheatomicradiusforthe Period 3 elements. [1]
58 Explain, in terms of electrons, the change in radius when a sodium atom becomes a sodium ion. [1]
13 124
14 114
Atomic Number
Atomic Radius (pm)
11
160.
12
140.
13
124
14
114
15
109
16
104
17
100.
18
101
55 On the grid in your answer booklet, mark an appropriate scale on the axis labeled
“Atomic Radius (pm).” [1]
56 On the grid in your answer booklet, plot the data from the data table. Circle and connect the points. [1]
57
57 Statethegeneralrelationshipbetweentheatomicnumberandtheatomicradiusforthe 58 Period 3 elements. [1]
Example of a 2-credit response for questions 55 a
Atomic Radius Versus Atomic Number
200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10
0
Jan 2013 #55-58
11 12 13 14 15 16 17 18
Atomic Number
58 Explain, in terms of electrons, the change in radius when a sodium atom becomes a
sodium ion.
55 [1] Allow 1 credit for marking an appropriate scale. An appropriate scale is linear and allows a trend to [1] be seen.
nd 56:
Explanation: Number the intervals on the Atomic Radius axis. You must start with zero and include the numbers from the chart (100-160).
57 [1] Allow 1 credit. Acceptable responses include, but are not limited to: As atomic number increases, there is a decrease in atomic radius.
P.S./Chem.–Jan. ’13 [10]
56 [1] Allow 1 credit for plotting all eight points correctly 􏰁 0.3 grid space. Plotted points do not need to be circled or connected.
55,56) Answer:
Answer
57) Answer: As the atomic number increases, the atomic radius
[10]
11 12 13 14 15 16 17 18
Atomic Number
58 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
decreases.
58) Answer: The radius of a sodium ion is smaller because the sodium atom lost one electron.
Explanation:
1. Find the symbol of sodium on Table S (pg. 10). The symbol for
sodium is ‘Na’.
2. Find Na on the Periodic Table.
‘Na’ has a +1 ion, which means that it gave away one electron. Since the ion gave away an electron, it is smaller than the atom.
P.S./Chem. Answer Booklet–Jan. ’13 [2]
Atomic Radius Versus Atomic Number
/Chem.–Jan. ’13
Atomic Radius (pm)
Atomic Radius (pm)
UNIT 3: PERIODIC TABLE OF ELEMENTS © 85
The radius of a sodium ion is smaller because the sodium atom lost one electron.