Transcript Back to Atoms and their bits…

Study for the quiz!
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What did Rutherford show with his Gold
Foil Experiment?
What is the name of Group 7/17?
What reacts with the Noble Gasses?
A member of Group 1 joins with a
member of Group 7 to form a ________
How many electrons are in the outer
layer of Oxygen?
Practical vs. Applied
Science
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Practical Science – research of
atoms
Applied Science – application of
what was being learned. Was
happening all along with the
development of the Atomic Theory.
The Nucleus
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It’s where the protons and neutrons
live.
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Weight? (Atomic Mass Unit)
Charge?
How can we tell how many are in an
atom?
What element’s nucleus is 1 proton?
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Weight?
Charge?
Where located?
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Weight?
Charge?
Where located?
How can we tell how many in an
atom?
But when, Mr. Brady, will I encounter
electrons?
Positives & Negatives
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What do unlike charges do? Attract
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What do like charges do? Repel.
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What does this mean for protons and
electrons?
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Add or subtract electrons – you have an
ion.
Definition: an atom where the total
number of electrons is not equal to the
total number of protons, giving it a net
positive or negative charge.
Anion – more electrons than protons,
negative charge
Cation – more protons than electrons,
positive charge
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Add a neutron to a nucleus – do you
still have the same element?
You have an isotope.
Isotope: the same element as before,
but with a different number of
neutrons.
Usually named by their mass number
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Isotopes – add neutrons
Ions – add or subtract electrons
Proton
Neutron
Electron
Atomic Mass
Atomic Number
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They aren’t in specific “orbits” –
they’re in a “cloud” – and electron
cloud, which is better represented like
this:
The probable location
of the electrons
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Still, we say that electrons spin around
the nucleus in certain energy levels, or
shells.
The electrons around a nucleus can be
found in one of seven shells. Each
shell can hold a set number of
electrons.
Each shell can hold 2n2 electrons,
where n is the shell number.
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Oxygen – 8 electrons. Where are they?
Shell 1 – 2(1)2 = 2 electrons
Shell 2 – (can hold 8) = 6 electrons
Electrons fill shells before moving
on to the next
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How many electrons? 6
Where are the electrons located?
2 in shell 1, 4 in shell 2.
Sodium11p
Chlorine 17e
Argon 18e
Carbon 6e
Oxygen 8e
Neon 10e
Hydrogen 1e
Helium 2e
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Atoms want their shells full.
Outermost shell is called the valence
shell
Electrons in the outermost shell are
called valence electrons
These are where the action is at.
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The further out the shells are, the
higher the energy state
There are seven shells – how many
periods are there in the Periodic Table?
That is to say…
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Shells correspond to the Periods of the
Periodic Table.
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Atoms want their valence shells to be
full, WITH 8 ELECTRONS. Full shells =
lower energy state.
The closer they are to full, the more
reactive the atom is.
Think about this in terms of the
Groups.
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Those that have more, want more –
the halogens & neighbors.
Those that have the least, give the
most – the alkalis and neighbors.
Halogens – just need one
Alkalis – just have one
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Valence electrons – where it’s at.
Periods – correspond to the shells
For Groups 1-8 (skipping Transition
Metals), the # of valence electrons =
Group # in Periodic Table
By Groups – see the same number of
valence electrons. Elements in Groups
share reactivity, remember?
Arts & Crafts 
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Build a Bohr Model.
Select an element
Pick out your parts
Format it correctly, and place
everything in the right spot.