Download Subatomic Heavyweights

Subatomic Heavyweights
Opening Questions
neutron
1. What is different about the two atoms above?
2. What is the atomic number of each atom above?
3. What is the mass number of each atom?
4. Do you think they are both lithium atoms? Why?
What’s an isotope?
neutron
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Both atoms are Lithium—same number of
protons as the atomic number of Lithium
These atoms are ISOTOPES of one another.
What’s an isotope?
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Isotopes: Atoms of the same element that have
different numbers of neutrons.
Because of the different numbers of neutrons,
the atoms have different masses.
neutron
Lithium-6
Lithium-7
Subatomic Heavyweights Summary
Atoms of the same element will ALWAYS have
the same number of protons
• Atomic weight: the weighted average atomic
mass of the naturally occurring isotopes (the #
on the periodic table)
•
•
To find the most common isotope: round the
atomic weight to the nearest whole number
Subatomic Heavyweights Summary
Isotope notation:
Mass number
Atomic number
The above can also be written as:
cobalt-59
Wrap-Up
How do potassium-39, potassium-40, and
potassium-41 differ from each other?
How many electrons, protons, and neutrons are
contained in each of the following atoms?
1.
2.
a.
b.
Fluorine-23
Molybdenum-96
c.
3.
What is the atomic weight of phosphorus?
What is its atomic number? Predict which
isotope you would find in greatest abundance
for phosphorus.