Download File

Station 1: Isotopes
All atoms of the same element have the same number of protons, but the number of neutrons may vary.
Isotopes are atoms of the same element, which have different numbers of neutrons.
Complete the following table for the 3 commonly occurring isotopes of oxygen.
Isotope
Nuclear
Symbol
Number of
Protons
Number of
Electrons
Number
of Neutrons
Mass
Number
Mass (amu)
Oxygen – 16
15.99415
Oxygen – 17
16.999131
Oxygen - 18
17.999160
What structural characteristics do all oxygen atoms have in common?
What differences exist between the isotopes of oxygen?
The isotopes of an element do not differ significantly in their chemical behavior. Why do you think this is so?
Station 2: Atomic Mass and Percent Abundance
The average atomic mass for an element is given on the periodic table, but how was it determined?
In order to calculate the average atomic mass for an element, you must know the percent abundance and atomic mass for each
of the isotopes of that element.
Example Problem
Isotope
Atomic Mass
Percent
Abundance
Oxygen – 16
15.99415 amu
99.762%
Oxygen – 17
16.999131 amu
0.038%
Oxygen – 18
17.999160 amu
0.200%
The average atomic mass of oxygen is given as 15.999 amu on the periodic table. Let’s see how that was calculated
15.99415 amu x (99.762 / 100) = 15.95608 amu
16.99415 amu x (0.038 / 100) = 0.0064597 amu
17.99160 amu x (0.200 /100) = 0.03598 amu
15.95608 amu + 0.0064597 amu + 0.03598 amu = 15.999 amu
A certain element exists as three natural isotopes as shown in the table below.
Isotope
Mass (amu)
Percent
Abundance
Mass Number
1
19.99244
90.51
20
2
20.99395
0.27
21
3
21.99138
9.22
22
Calculate the average atomic mass of this element to the nearest thousandth.
Identify the Element.
Station 3: Isotopes and Abundance
Carbon has three naturally occurring isotopes: Carbon-12 (12.000 amu), Carbon-13 (13.003 amu), and Carbon-14 (14.003
amu). Based upon the average atomic mass of carbon (12.011 amu), which isotope of carbon do you think is the most
abundant in nature? Explain your answer.
An element has two naturally occurring isotopes. The mass of the first isotope is 64.9278 amu and the mass of the second
isotope is 62.9296 amu. The average atomic mass of the element is 63.546 amu. Calculate the percent abundance of each
isotope to two decimal places.
Let x = the percent as a decimal of the first isotope.
1-x = the percent as a decimal of the second isotope
Station 4: Beanium Review
Period 1 and 4:
Take time now to make sure your data table is complete for your Beanium activity we completed on Friday. If you did not get
mass make sure to get that information from a classmate now. Check your calculations. Based on the lab activity answer the
following question:
How did the Beanium lab represent different isotopes of an atom? How were the isotopes used to calculate the average atomic
mass written on the periodic table?
Using the average atomic mass you calculated create a periodic table symbol of Beanium – abbreviation Bu (include atomic
number, symbol, and average atomic mass) Indicate which elements it would be near on the periodic table if added.
Period 3:
the data is being provided to you now. Complete the calculations for the Beanium activity using the instructions provided.
Based on the lab activity answer the following question:
How did the Beanium lab represent different isotopes of an atom? How were the isotopes used to calculate the average atomic
mass written on the periodic table?
Using the average atomic mass you calculated create a periodic table symbol of Beanium – abbreviation Bu (include atomic
number, symbol, and average atomic mass) Indicate which elements it would be near on the periodic table if added.
Station 5: Cl-Ev-R summary of Beanium
Use the following format to create a lab summary report based on your Beanium Lab : How do the different beanium isotopes
represent an isotope in real life ?
Start your Claim based on what you know about Isotopes. This Report is due on Friday September 13, 2013. Each Table should
translate into a paragraph. It must be TYPED, Times New Roman, 12 font, Double spaced. Remember your title requirement in
your syllabus.
Station 6: Ions
Ions are formed when an atom gains or loses electrons.
• anion – negatively charged ion formed when an atom gains electrons
• cation – positively charged ion formed when an atom loses electrons
Atomic Number
• determined by the number of protons in the nucleus
• found on the periodic table
Determine the atomic number for each of the following elements.
Li
3
N
7
Mg
12
Mass Number
• equal to the sum of the neutrons and protons in the nucleus of an atom
• not given on the periodic table
Ways to indicate mass number:
Hyphen notation Chlorine - 35
Nuclear Symbol
1. Write the hyphen notation and nuclear symbol for the element containing 4 protons and 5 neutrons.
2. Determine the number of neutrons in Argon-4
Complete the following table:
Element
(hyphen
notation)
Nuclear
Symbol
Number Number Number
Atomic
Mass
of
of
of
Number Number
Protons Neutrons Electrons
22
Sodium -22
9
19
9
80
40
45
20
0