Where are electrons found?

1
Where are electrons found?

• Heisenberg uncertainty principle
• It is impossible to know both the momentum and
  the position of a particle with certainty.
• However, we can use the Schrodinger equation to
  estimate where an electron is likely to be found.
  The Schrodinger equation is given above. It is
  third year college Chemistry, you do not need to
  know anything about it, except that it exists.

2
The schroedinger equation describes the orbitals
in which electrons are found.

• Quantum numbers are used to describe the position
  of electrons.
• N the energy level
• L the angular momentum (shape of orbitals)
• M magnetic quantum number (orientation)
• S spin quantum number (clockwise or
  counterclockwise)

3
Electrons fill lowest energy levels first.

• The s orbital is the simplest orbital.
• The 1s orbital is the lowest energy orbital.
• 2 s orbital is the second lowest energy orbital.
• Two electrons can fit in any orbital.

4
Once the lowest energy level is filled, the next
energy level begins to fill.

• The second lowest energy type of orbital are p
  orbitals.
• Each p orbital holds two electrons.
• 3 sets of two electrons is a total of 6 electrons.

5
d-orbitals are more complex.

• There are no 1d or 2d orbitals.
• d orbitals do not begin to get filled until after
  the 4s orbital is filled.
• There are five sets of d orbitals, two electrons
  each for a total of 10 electrons in the d
  orbitals.

6
f orbitals are only used for elements in period 6
and 7

• There are seven types of orbitals, two electrons
  each.

7
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hydrogen has one proton, one electron.
H 1s1
8
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Helium has two protons, two electrons.
He 1s2
9
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
One less electron and lithium has a full set of
electrons we can predict that lithium will be
very reactive. And in fact, lithium reacts with
water to produce a gorgeous red flame!
Lithium has three protons, three electrons.
Li 1s22s1
10
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Beryllium has four protons, four electrons.
Be 1s22s2
11
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
boron has five protons, five electrons.
B 1s22s22p1
12
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Carbon has six protons, six electrons.
C 1s22s22p2
13
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Nitrogen has seven protons, seven electrons.
N 1s22s22p3
14
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Oxygen has eight protons, eight electrons.
O 1s22s22p4
15
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Fluorine has nine protons, nine electrons.
One more electron and fluorine has a full set of
electrons we can predict that fluorine will be
very reactive.
F 1s22s22p5
16
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Neon has ten protons, ten electrons.
Neon is a noble gas, it tends not to react. We
saw its spectrum was a gorgeous red, with green
and yellow. It is used for lights BECAUSE it
doesnt react.
Ne 1s22s22p6
17
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Sodium has eleven protons, eleven electrons.
One less electron and sodium has a full set of
electrons we can predict that sodium will be very
reactive. If you remember the flame test, you
will remember that sodium had a yellow-orange
flame. When you put sodium in water, it catches
fire and gives a bright yellow flame.
Na 1s22s22p63s1
18
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Lets skip to potassium, atomic number 19
One less electron and potassium has a full set of
electrons we can predict that potassium will be
very reactive. If you remember the flame test,
you will remember that potassium had a violet
flame. When you put potassium in water, it
catches fire and gives a violet flame.
K 1s22s22p63s23p64s1
19
Electrons fill orbitals one at a time, beginning
at 1s and increasing energy until all the
electrons have a unique spot.
The Aufbau Principle Electrons fill the lowest
energy levels first
Hunds Rule One electron in each orbital before
two electrons In any orbital.
Lets skip to chromium, atomic number 24 Cr
1s22s22p63s23p64s23d4
If we move an electron from 4s to 3d, we get a
symmetrical electron configuration. This
is energetically favored. Cr
1s22s22p63s23p64s13d5