The Bohr Model of the Atom
DO NOT WRITE ON THESE NOTESCOPY THESE NOTES IN CORNELL
STYLE IN YOURBINDER.
What do we need to know?
• Atoms have 2 main parts
– Electron cloud -- contains electrons
– Nucleus – central part of the atom, contains protons and neutrons
Subatomic particles
• Symbols for each subatomic particle
– Electrons = e- (found in the electron cloud)– Protons = p+ (found in the nucleus)– Neutrons = n0 (found in the nucleus)
What do you need to know?
• Orbitals are found around the nucleus
– There are 7 possible orbitals
– Orbitals are determined by looking at what PERIOD (row) the element is in
– The orbitals hold a specific number of electrons (which is the same as the atomic number)
Period 1
Period 2
Period 3
Period 4
Period 5
Period 6
Period 7
How many electrons per orbital?Period 1 orbital (ring) 1: 2 e-
Period 2 orbital (ring) 1: 2 e- orbital (ring) 2: 8 e- Period 3 orbital (ring) 1: 2 e- orbital (ring) 2: 8 e- orbital (ring) 3: 8 e- Period 4 orbital (ring) 1: 2 e- orbital (ring) 2: 8 e- orbital (ring) 3: 18 e-
orbital (ring) 4: 8 e-
Information to create a Bohr model
• Element name and symbol:– Magnesium (Mg)– Atomic number: 12– Atomic mass: 24– Protons: 12– Electrons: 12– Neutrons: (24 - 12) = 12
12
Mg
24.305
Magnesium
Atomic # = Protons and Electrons
Atomic Mass
Atomic Mass – Atomic # = Neutrons
Bohr model for Mg
12p+
12n0
Nucleus
Orbital 1 can only hold a maximumof 2 electrons
Orbital 2 can only hold a maximum of 8 electrons
Orbital 3 can only hold a maximum of 8 electrons, but you only use the # of electrons you need.
Electrons are represented by the dots.
Magnesium will have 3 orbitals because it is in period #3
When you add all the dots (electrons) you should get 12.
Bohr model for Al
• Aluminum is in period #3 and has 13 electrons.
13p+
14n0
Your Assignment!This goes on a separate piece of
paper!• Create the Bohr model for elements 1-20 on the
periodic table. (Hydrogen (H) – Calcium (Ca))
• For each element provide the: – Write the element name: __________________– Protons= ____– Electrons= ____– Neutrons= ____– Period = _____ = Orbitals= _____– Bohr Model: