Name: ______ANSWER KEY_________________________ Date: ____________________________ Period: __________
An Investigation into Isotopes
Objectives:
-
To use the periodic table to correctly identify the number of protons, neutrons, and electrons for any element.
To be able to identifyi similarities/differences between isotopes of the same element
To correctly locate each of these subatomic particles within the atom.
Important Points to review what we’ve learned so far:
1. Atoms are made up of protons, neutrons, & electrons. Write the charge of each subatomic particle.
(a.)
protons: +
(b.)
neutrons: 0
(c.)
electrons: -
2. In a neutral atom, the number of electrons is always equal to the number of protons.
3. The atomic number of an element tells us the number of protons.
4. The mass number of an isotope tells us the number of protons and neutrons.
5. If we wanted to write out the symbol for the isotope of chlorine with a mass number of 37, there are 2 ways:
(a.)
hyphen-notation: chlorine-37
(b.)
nuclear symbol:
37
17Cl
6. Isotopes are atoms of the same element that have different masses.
7. Isotopes have the same number of protons, but a different number of neutrons.
8. To get the # of neutrons for an isotope, you subtract the mass number & number of protons.
Fruit Loop Activity
11. You need to decide on fruit loop colors for each of the following subatomic particles. Write in the blank provided
what color of fruit loop will represent each particle.
Protons:
(red) varies
Neutrons: (blue) varies
Part A: Hydrogen Isotopes
Using the colors you have chosen, construct a model of the nucleus of the three hydrogen isotopes shown in the table
below. Draw a colored sketch of your model below:
Hydrogen-1
Hydrogen-2
Hydrogen-3
Fill in the missing information in the table below for each isotope of hydrogen:
Isotope
Atomic Number
Mass Number
# protons
# neutrons
# electrons
Nuclear Symbol
Hydrogen-1
1
1
1
0
1
1
H
1
Hydrogen-2
1
2
1
1
1
2
H
1
Hydrogen-3
1
3
1
2
1
3
H
1
Part B: Carbon Isotopes
Using the same colors you have chosen, construct a model of the nucleus of the three carbon isotopes shown in the
table below. Draw a colored sketch of your model below:
Carbon-12
Carbon-13
Carbon-14
Fill in the missing information in the table below for each isotope of carbon:
Isotope
Atomic Number
Mass Number
# protons
# neutrons
# electrons
Nuclear Symbol
Carbon-12
6
12
6
6
6
12
C
6
Carbon-13
6
13
6
7
6
13
C
6
Carbon-14
6
14
6
8
6
14
6C
Part C: Fluorine Isotopes
Using the same colors you have chosen, construct a model of the nucleus of the three fluorine isotopes shown in the
table below. Draw a colored sketch of your model below:
Fluorine-18
Fluorine-19
Fluorine-20
17. Fill in the missing information in the table below for each isotope of fluorine:
Isotope
Atomic Number
Mass Number
# protons
# neutrons
# electrons
Nuclear Symbol
Fluorine-18
9
18
9
9
9
18
F
9
Fluorine-19
9
19
9
10
9
19
F
9
Questions
1. Which subatomic particle identifies an atom as that of a particular element? proton
2. How is this particle related to the atom’s atomic number? Equal to it
3. Which subatomic particles account for most of an atom’s mass? Protons & neutrons
Fluorine-20
9
20
9
11
9
20
F
9
Give the symbol and number of protons in one atom of:
Lithium Li, 3
Bromine Br, 35
Bismuth Bi, 83
Iron
Copper
Tin
Sn, 50
Sodium
Na, 11
Fe, 26
Oxygen O, 8
Cu, 29
Mercury Hg, 80
Give the symbol and number of electrons in a neutral atom of:
Uranium U, 92
Chlorine
Iodine
Antimony Sb, 51
Xenon Xe, 54
Yttrium
Lead
I, 53
Manganese Mn, 25
Cl, 17
Y, 39
Boron
B, 5
Pb, 82
Determine the number of protons and neutrons for the following isotopes:
(a.) sodium-23
#p = 11
#n = 12
#p = 29
#n = 35
(c.) calcium-40
#p = 20
#n = 20
108
Ag
47
#p = 47
#n = 61
(e.) silver-108
#p = 47
#n = 61
(f.) bromine-80
#p = 35
#n = 45
(b.)
(d.)
64
Cu
29
Write the nuclear symbol & hyphen notation for each of the following isotopes:
(a.)
mass number of 28 and atomic number of 14
14Si, silicon-28
(b.)
26 protons and 30 neutrons
56
26Fe, iron-56
(c.)
28
atomic number = 2, mass number = 4
He, helium-4
2
4
(d.)
47 protons and 49 neutrons
silver-96
96
47Ag,
(e.)
atomic number = 19, mass number = 39
39
19K, potassium-39
If you know only the following information can you always determine what the element is? (Yes/No).
(a.)
number of protons
yes
(b.)
number of neutrons
no
(c.)
number of electrons in a neutral atom
yes
Extension Opportunity: Which isotope of carbon is most common? How did you determine this? (Cite specific
evidence). Explanations will vary. carbon-12 (98.89% abundance)