C2 – Bohr Models
What do you know about…
•Protons
What do you know about…
•Neutrons
What do you know about…
•Electrons
Atomic Number
• # of protons
• # of electrons
• APE
• Atomic number = # of
protons = # of electrons
• Always the smaller
number
Mass
• Mass of an atom of the element
• Total number of protons + neutrons
• Electrons are not included because they are very
light
• Mass – atomic number = # of neutrons
Magnesium
• Atomic number = 12
• Atomic mass number = 24
• Protons = 12
• Electrons = 12
• Neutrons = 12
Chlorine
• Atomic number = 17
• Atomic mass number = 35
• Protons = 17
• Electrons = 17
• Neutrons = 18
Atomic
Number
Mass
Number of
Protons
Number of
Neutrons
Number of
Electrons
Element
9
19
9
10
9
Fluorine
14
7
20
13
27
56
26
20
Atomic
Number
Mass Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
Element
9
19
9
10
9
Fluorine
7
14
7
7
7
Nitrogen
20
20
13
27
56
26
Atomic
Number
Mass Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
Element
9
19
9
10
9
Fluorine
7
14
7
7
7
Nitrogen
20
40
20
20
20
Calcium
13
27
56
26
Atomic
Number
Mass Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
Element
9
19
9
10
9
Fluorine
7
14
7
7
7
Nitrogen
20
40
20
20
20
Calcium
13
27
13
14
13
Aluminum
56
26
Atomic
Number
Mass Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
Element
9
19
9
10
9
Fluorine
7
14
7
7
7
Nitrogen
20
40
20
20
20
Calcium
13
27
13
14
13
Aluminum
26
56
26
30
26
Iron
Questions
• Distinguish between atomic mass and atomic
number.
• Distinguish which particles can be used to
identify an element.
• Determine which particles represent the mass of
an atom.
Assignment
• Complete “Determining the Number of atomic
particles” worksheet
Bohr Model
• 3 electron orbits (shells)
• 1st shell; two electrons
• 2nd shell; eight electrons
• 3rd shell; eight electrons
1 Electron Shell
Helium
2 Electron Shells
Neon
3 Electron Shells
Chlorine
Electron Shells
• 1st then 2nd then 3rd
• Order of filling shells
• The exact position of
electrons within the shell
cannot be determined
Oxygen Bohr Model
• Atomic Number = 8
• Mass = 16
• Protons = 8
• Neutrons = 16 – 8 = 8
• Electrons = 8
• 1st shell = 2
• 2nd shell = 6
Neon Bohr Model
• Atomic Number = 10
• Mass = 20
• Protons = 10
• Neutrons = 20 – 10 = 10
• Electrons = 10
• 1st shell = 2
• 2nd shell = 8
• Full outer shell
Sodium Bohr Model
• Atomic Number = 11
• Mass = 23
• Protons = 11
• Neutrons = 23 – 11 = 12
• Electrons = 11
• 1st shell = 2
• 2nd shell = 8
• 3rd shell = 1
Magnesium Bohr Model
• Atomic Number = 12
• Mass = 24
• Protons = 12
• Neutrons = 24 – 12 = 12
• Electrons = 12
• 1st shell = 2
• 2nd shell = 8
• 3rd shell = 2
Helium
Boron
Chlorine
Assignment
• Complete Bohr-Rutherford Diagram of the first 20 elements
• Only do first 18, ignore K and Ca
Fluorine Bohr Model
• Atomic Number = 9
• Mass = 19
• Protons = 9
• Neutrons = 19 – 9 = 10
• Electrons = 9
• 1st shell = 2
• 2nd shell = 7
Hydrogen Bohr Model