Download Bohr Model Diagrams

ChemCatalyst 10/26/15
Today you need your laptop (go to weebly) and notebook.
In your notebook answer the following questions:
1. How many protons, electrons, and neutrons are in
the following atom.
Bohr Model
Atoms can be represented by Bohr diagrams. Bohr
diagrams are useful for:
① Better understanding the properties of an element
② Predicting how an atom can combine with others to
form compounds
Are only useful in portraying the first 20 elements
because it breaks down after the first 20!
That is to say, it is a simple theory which works for
simpler atoms. When you get past 20 the electronic
structures are more complex and the theory cannot
deal with them.
Bohr Model Diagram
In this model of the atom, the electrons travel around the
nucleus in well defined circular paths known as orbital or
energy shells.
Each electron in an atom has a definite amount of
energy
The farther away the electron is from the nucleus, the
great the energy
Electrons cannot exit between orbital, but can only move
up or down from one orbital to another.
Electrons in the Energy Levels:
0 The orbits can hold only a specific
number of electrons
0 Once a level is full, the electrons start
filling the next level.
ELECTRON LEVEL LIMITS:
(filling order limits)
1st level = 2 electrons
2nd level = 8 electrons
3rd level = 8 electrons
4th level = 18 electrons
Steps for Drawing Bohr Model
① Determine the number of electrons, protons, and
neutrons to be drawn:
# protons = atomic number
# electrons = atomic number
# neutrons = atomic mass – atomic
number
① Draw a circle for the nucleus and write the number of
protons and neutrons.
② Draw a larger orbital/circle around the nucleus.
③ Fill the orbital and draw more using the following:
• 1st Orbital (nearest to the nucleus): filled first, with a
maximum of 2 electrons
• 2nd Orbital: fill with a maximum of 8 electrons (draw in
electron pairs for more than four electrons in orbital)
• 3rd Orbital fill with a maximum of 8 electrons
• 4th Orbital fill with a maximum of 18 electrons
Classroom Example: Helium
e
P+ = 2
N0 = 2
e
# protons: 2
# electrons: 2
# neutrons: 2
① Determine the number of
electrons, protons, and
neutrons to be drawn:
② Draw a circle for the
nucleus and write the
number of protons and
neutrons.
③ Draw a larger orbital/circle
around the nucleus.
④ Fill the orbital and draw
more using filling rules
Classroom Example: Carbon
e
e
e
P+ = 6
N0 = 6
e
e
# protons: 6
# electrons: 6
# neutrons: 6
e
① Determine the number of
electrons, protons, and
neutrons to be drawn:
② Draw a circle for the
nucleus and write the
number of protons and
neutrons.
③ Draw a larger
orbital/circle around the
nucleus.
④ Fill the orbital and draw
more using filling rules
Hope this presentation
wasn’t too Bohr-ing