Download Chapter 11 section 2 questions - the atom

Chapter 11 section 2 questions ­ the atom
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September 21, 2012
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Describe the size of an atom.
A penny contains 20,000,000,000,000,000,000,000 atoms of copper and zinc. Aluminum atoms have a diameter of 0.00000003 cm (3 one hundred millionths).
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Name the parts of an atom.
proton
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neutron
electron
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Describe the relationship between numbers of
protons, neutrons, and atomic number.
Protons and neutrons are found in the nucleus and make up 99% of the mass of an
atom (measured in AMU - atomic mass units).
If you add protons and neutrons together they EQUAL the atomic mass.
The number of Protons will ALWAYS remain the SAME for an element. If the number of
protons changes - the element changes.
The number of protons is ALWAYS EQUAL to the ATOMIC NUMBER!!
To find the number of neutrons an atom is SUPPOSED to have, simply take the difference
between the atomic number and the atomic mass (rounded to the nearest whole number).
Sometimes the number of neutrons is different, thereby the element will have a different
atomic mass. When this happens (the number of neutrons is not what it's supposed to be)
we call it an ISOTOPE!!
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
State how Isotopes differ.
Isotopes have different atomic masses than what can be
calculated normally.
For Example: Helium has an atomic number of 2 and an
atomic mass of 4. Therefore, it has 2 protons and 2
neutrons. If Helium has 4 neutrons instead, it is an
ISOTOPE. We would write this Isotope as He-6. The 6
tells you the atomic mass of the element listed!!
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Describe the forces within an atom.
Gravitational - amount of force between 2 objects
Electromagnetic - Opposites attract (positive/negative)
Strong Force - in the nucleus
Weak Force - radioactive/unstable atoms
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Name the 2 kinds of particles that can be found in the nucleus.
Protons and Neutrons
What charge does the nucleus carry?
ALWAYS POSITIVE!!
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
How does an atom become a positively charged ion?
Electrons are the negatively charged particles found in the energy levels that surround
the nucleus - this like the rings on a target!
Electrons have a VERY small mass - almost inconsequential to the atomic mass.
Electrons carry a negative charge and are held in place by the positively charged
protons. (BTW...Neutrons are NEUTRAL!) In a neutral atom - the number of protons is
EQUAL to the number of electrons. Therefore they cancel each other out. Sometimes,
during the chemical bonding process atoms can gain or lose electrons in the formation of
new chemical bonds. When this happens an ION is formed. SO, if you have a POSITIVE
ION - you have more protons than electrons (you lost electrons during the bonding
process). If you have a NEGATIVE ION - you have more electrons that protons (you
gained electrons during the bonding process). More on this as we progress:)
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
In what cases are different isotopes important?
They still have the same basic properties as the original atom. However, sometimes
isotopes can be radioactive (or unstable). Meaning that they can change spontaneously.
These radioactive isotopes are known for being used mostly in a lab setting. For example:
Carbon-14 is used in radioactive dating materials that are believed to be no more than
50,000 years old.
Ummmmm....
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Draw and Label a model of a Helium (neutral) atom.
Proton
Electron
Neutrons
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Draw and label a model of 2 different Hydrogen isotopes.
Hydrogen Atom
Neutral!
Hydrogen Atom
Neutral!!
Hydrogen­1
Hydrogen­2
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Chapter 11 section 2 questions ­ the atom
September 21, 2012
Math Focus...Calculating Atomic Mass
1. (.2 X 10 amu) + (.8 X 11 amu) = 10.8 amu
2. (.72 X 85 amu) + (.28 X 87 amu) = 85.56 amu
3. (.6 X 69 amu) + (.4 X 71 amu) = 69.8 amu
4. (.52 X 107 amu) + (.48 X 109 amu) = 107.96 amu
5. (.92 X 28 amu) + (.05 X 29 amu) + (.03 X 30 amu) = 28.11 amu
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