Transcript Electron Configurations

Electron
Configurations
Don’t worry. Ya’ll got this! It’s not as difficult as it
sounds!
So, this is what you’ll learn today:
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You will learn that an atom is made up of mostly “empty space”
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Electrons, and how they are positioned in the atom, determine how that
atom might react with other atoms
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You will learn how to write an electron configuration for any element on the
Periodic Table
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Lewis dot structures are another type of notation that will help you visualize
an atom’s valence electrons
Ok, get ready, cuz we’re about to do
some Chemistry!
This is an atom.
This is the
extremely vast
and empty-ish
electron cloud….
This is a teeny, tiny
nucleus.
The electrons in an atom,
because they are moving
particles, have wave
characteristics.
We can attempt to predict an electron’s
location in an atom based on the wave
functions of the electrons.
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An atomic orbital is a 3-D region
around the nucleus that describes an
electron’s probable location in the
atom.
• The
more dense the
“cloud” is, the more
likely the electron is
there.
Principal Quantum Numbers (n)
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Indicate the relative sizes and
energies of atomic orbitals.
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An n increases, the atomic orbital
becomes larger, and the electron
spends more time farther from the
nucleus. The atom’s energy level
increases.
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Because of this, n specifies the
atom’s major energy levels, called
principal energy levels
So, let’s recap…..
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An atom’s electrons move around constantly and are NOT
in fixed orbits like Neils Bohr thought.
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The electrons move because of the energy that is
associated with that atom.
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We need to understand the arrangements of the electrons
so that we can predict how the atom will react with other
atoms.
Energy and Stability
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Low-energy systems are more stable than high-energy systems.
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What do we mean by stable?
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An atoms “wants” to be stable….. If it has high energy, it is less
stable.
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So, electrons tend to arrange themselves in such a way that gives the
atom the lowest possible energy, which is called the ground-state
electron configuration
There are seven principal quantum
numbers (n)……
A different look to the Periodic Table
They just so happen to be arranged
in order in the Periodic Table
Each principal quantum number has
sublevels associated with it
•
Remember this?
The sublevels are, in order of increasing
energy:
s, p, d and f