Name:
Aim 37: Isotopes
Date:
Based on the diagram above, name 3 things you notice between the three isotopes of Carbon.
1.
2.
3.
I.
What is an Isotope?
All atoms of the same element have the same number of protons. But some have a different number of neutrons.
For example, the carbon element from the diagram above shows that they all have the same number of protons but
different number of neutrons.
1) Define Isotope:
2) Will the atomic number for isotopes of an element change? ________ Explain why:
3) Will the mass number for isotopes of an element change? __________ Explain why:
4) Do all isotopes of the same element have the same # of
Protons? ________ Electrons? __________ Neutrons? ________
II.
How are isotopes named?
Since the number of neutrons is what differs between isotopes, they are named based on their mass number. For
example, Carbon-12 or C-12 means that we are talking about an isotope of carbon with an atomic mass of 12. If we
are talking about Carbon – 14 or C-14, we are talking about an isotope of carbon with an atomic mass of 14.
a. The element is: __________________
b. The number 3 refers to the _________________________
c. The numbers 6, 7, and 8 refer to the ________________________ Why is it different for each isotope?
d.
e. How many protons and neutrons are in the first isotope?
f.
P = __________ N = ___________
How many protons and neutrons are in the second isotope? P = __________ N = ___________
g. How many protons and neutrons are in the third isotope?
P = __________ N = ___________
h. Why isn’t the atomic number written after the dash for the isotopes?
For each of the questions below fill in the atomic number, mass number, and write the proper name
(ex: hydrogen-2) for each isotope.
2. Carbon (6 protons, 8 neutrons)
Atomic number ______ Mass number ______ Name ________________
3. Argon (18 protons, 22 neutrons)
Atomic number ______ Mass number ______ Name ________________
4. Silver (47 protons, 61 neutrons)
Atomic number ______ Mass number ______ Name ________________
5. Protactinium (91 protons, 142 neutrons)
Atomic number ______ Mass number ______ Name ________________
Complete the following chart
Isotope Name
Uranium – 235
Uranium – 238
Boron – 10
Boron – 11
Atomic #
Mass #
# of protons
# of neutrons
# of electrons