helium atom + n n + - - proton electron neutron shell what do these particles consist of?
TRANSCRIPT
HELIUM ATOM
+N
N
+-
-
proton
electron
neutron
Shell
What do these particles consist of?
ATOMIC STRUCTUREATOMIC STRUCTURE
Particle
proton
neutron
electron
Charge
+ ve charge
-ve charge
No charge
1
1
nil
Mass
ATOMIC STRUCTUREATOMIC STRUCTURE
the number of protons in an atom
the number of protons and neutrons in an atom
HeHe22
44 Atomic mass
Atomic number
number of electrons = number of protons
ATOMIC STRUCTUREATOMIC STRUCTURE
Electrons are arranged in Energy Levels
or Shells around the nucleus of an atom.
• first shell a maximum of 2 electrons
• second shell a maximum of 8
electrons
• third shell a maximum of 8
electrons
ATOMIC STRUCTUREATOMIC STRUCTURE
Three ways to represent the atomic structure
of an element or compound;
1. Lewis Notation
2. Rutherford-Bohr Model
3. The Ball and Stick Model
Determine the number of shells and the number of valence electrons for:
Determine the number of shells and the number of valence electrons for:
• Helium is the exception in Group 8.
• Since it has just one shell, that shell can only fit 2 electrons instead of 8.
• It is in this group because all the elements have a full outer shell.
Lewis Electron Dot Diagrams
Invented by the American chemist, G.N. Lewis.
1. Write the chemical symbol
2. Write the appropriate number of dots in a clockwise manner
Lewis Structures
1) Write the element symbol.
2) Carbon is in the 4th group, so it has 4 valence electrons.
3) Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.
Lewis Structures
1) Check your work.
2) Using your periodic table, check that Carbon is in the 4th group.
3) You should have 4 total electrons, or dots, drawn in for Carbon.
Lewis Structures
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
Lewis Structures
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
Lewis Structures
On your worksheet, try these elements on your own:
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
Lewis Structures
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
Lewis Structures
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
Lewis Structures
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
Lewis Structures
a) H
b) P
c) Ca
d) Ar
e) Cl
f) Al
BOHR-RUTHERFORD DIAGRAMS
Bohr-Rutherford diagrams should be drawn using the following steps:
Draw the nucleus with the proper number of protons (+1) and neutrons (0).
Draw the first electron shell with the appropriate number of electrons (-1).
BOHR-RUTHERFORD DIAGRAMS
Draw the second valence shell (if applicable) with the appropriate number of electrons (-1).
Continue to draw valence shells with electrons until you have the proper number of electrons for the element.
Example: sulfur
EXAMPLES
• Draw the Bohr-Rutherford Diagram for:
•Mg & Ca
Magnesium (Mg) and calcium (Ca)