#### Transcript Bohr Model - OCPS TeacherPress

```Vocabulary
• Bohr model
• Energy level (shell)
• Valence electrons
Bohr Model
• Electrons orbit the nucleus
of an atom in set energy
levels
P = 20
N = 20
Energy Level
• The specific energies an electron in an atom
can have
• In the Bohr model used to describe the
different orbits or shells that the electrons
travel in around the nucleus
Valence Electrons
• The electrons in the highest or
outermost energy level
Bohr Models are NOT Boring!
How to Draw Bohr Diagrams
Bohr models-a simple way to draw an
atom
• Bohr models are a way of showing the
electrons in an atom.
• Electrons are arranged in energy levels. In
actual atoms, those energy levels are clouds of
crazy shapes where the electrons are likely to
be found.
• Bohr models show the electron energy levels
in nice, neat, easy to draw circles.
Bohr Diagrams
1) Find the element on the periodic table.
2)Determine the number of electrons--it is the
same as the atomic number.
3)This is how many electrons you will draw.
Bohr Diagrams
1
• Find out which period
2
3
4
5
6
7
•Elements in the 1st period
have one energy level.
•Elements in the 2nd period
have two energy levels,
and so on.
www.chem4kids.com
The electron energy levels or shells surrounding
the nucleus each hold a particular number of
electrons.
Energy levels or shells are represented by n=
period number:
n=1
n=2
n=3
n=4
max 2 electrons
max 8 electrons
max 18 electrons
max 32 electrons
Remember: The outer shell of an atom (no
matter what letter) can only hold 8 electrons!
Max Electrons in each Energy Levels
2 electrons in 1st, 8 electrons in 2nd, 18 electrons in the 3rd, 32 electrons in the 4th
Things get a little crazy in the 3rd and 4th rings…8 go into the 3rd, then the
next 2 go into the 4th, then the electrons go back and fill up the 3rd
2e
P=
N=
8e
18 e
32 e
Max rule (2,8,18,32)
Fill rule (2,8,8,2 then rest in 3rd)
Bohr Diagrams
1) Draw a nucleus.
P=6
N=6
2)Write the number of
Protons and Neutrons the
element has inside the
nucleus.
Note: Round mass to nearest 1 when figuring neutrons.
Bohr Diagrams
P=6
N=6
1) Carbon is in the 2nd period,
so it has two energy levels,
or shells.
2) Draw the shells around the
nucleus.
Bohr Diagrams
P= 6
N=6
2) Carbon has 6 electrons.
3) The first shell can only
hold 2 electrons.
4) The second shell put the
remaining 4 electrons
Bohr Diagrams
H
P+ =
N0 =
Try Hydrogen:
Atomic Mass:
Atomic Number:
Protons:
Electrons:
Neutrons:
Shells:
Valence electrons:
Bohr Diagrams
H
P=1
N=0
Try Hydrogen:
Atomic Mass: 1.008
Atomic Number: 1
Protons: 1
Electrons: 1
Neutrons: 0
Shells: 1
Valence electrons: 1
Bohr Diagrams
Check Yourself.
P= 1
N= 0
H (1)
Bohr Diagrams
He
P=
N=
Try Helium:
Helium
Atomic Mass:
Atomic Number:
Protons:
Electrons:
Neutrons:
Shells:
Valence electrons:
Bohr Diagrams
He
P= 2
N= 2
Try Helium:
Helium
Atomic Mass: 4.003
Atomic Number: 2
Protons: 2
Electrons: 2
Neutrons: 2
Shells: 1
Valence electrons: 2
Bohr Diagrams
P= 2
N= 2
Check Yourself!
He (2)
Bohr Diagrams
O
P+=
N0=
Try Oxygen:
Atomic Mass:
Atomic Number:
Protons:
Electrons:
Neutrons:
Shells:
Valence electrons:
Bohr Diagrams
P= 8
N= 8
Try Oxygen:
Atomic Mass: 15.999
Atomic Number: 8
Protons: 8
Electrons: 8
Neutrons: 8
Shells: 2
Valence electrons: 6
Bohr Diagrams
Check Yourslef!
P= 8
N= 8
O (2,6)
Bohr Diagrams
P= 13
N= 14
Try Aluminum:
Atomic Mass: 26.982
Atomic Number: 13
Protons:13
Electrons:13
Neutrons:14
Shells:3
Valence electrons:3
Bohr Diagrams
Check Yourself!
Al (2,8,3)
P= 13
N= 14
Bohr Diagrams
P= 13
N= 14
Try Aluminum:
Atomic Mass: 26.982
Atomic Number: 13
Protons:13
Electrons:13
Neutrons:14
Shells:3
Valence electrons:3
Bohr Diagrams
P= 22
N= 26
Try Titanium (Ti) :
Atomic Mass: 47.88
Atomic Number: 22
Protons: 22
Electrons: 22
Neutrons: 26
Shells: 4
Valence electrons: 2
Bohr Diagrams
Check Yourself!
Ti (2,8,10,2)
P= 22
N= 26
```