# Atomic-Structure

Document Sample

```					Atomic Structure

Lesson Objectives:
1. To know what is atomic structure.
2. To be able to draw the structure of atoms of
the first 20 elements in the periodic table.
Look at the size of THAT!!
Measurements in metres
•   Distance to the sun          100,000,000,000
•   Height of Mt Everest                   10,000
•   Human                                      1.5
•   Grain of sand                          0.0001
•   Sugar molecule                  0.000000001
How small?!?!??
• If you pretended a whole atom was the
size the new Wembley Stadium, its
nucleus would be the size of a pea in the
middle of the pitch.
Let’s Model!!
What’s in an atom anyway?
There are 3 different particles within an
atom:

• Protons – with a charge of +1 and a mass of 1
• Neutrons – with no charge and a mass of 1
• Electrons – with a charge of -1 and a mass of
1/2000 (i.e. almost 0)
Where might one find these
particles?
• In the nucleus we find
neutrons and protons
(the big heavies).
• The overall charge of
the NUCLEUS is +
• Whizzing around the
nucleus are electrons
(the little guys).
What keeps it all together?
• The nucleus in an atom is positively charged
• Opposite charges attract each other so the
positive nucleus attracts the negative
electrons                    -ve electrons

-ve electrons
+ve nucleus

-ve electrons
Do the electrons just fly around at
random?
• Electrons are arranged in different shells around the nucleus.
• The innermost shell is filled first and then the rest until each is filled.
• There is a fixed number of electrons that each shell can hold.

shell      maximum number of electrons
first      2
second     8
third      8
fourth     18
Electron configuration
Do I know what is atomic structure?
• Complete the worksheet.
Atomic number
• Atoms are neutral (i.e. they have no
charge)
• So this means…………..
number of protons = number of electrons
• We call the number of protons an element
has the ATOMIC NUMBER (a.k.a. the
PROTON NUMBER)
Mass number
• Remember!!!!
– Protons have a mass of 1.
– Neutrons have a mass of 1.
– Electrons have a mass of 0 (almost).
So, every element….
• …has its own atomic number and it’s own
mass number.
Can I use this knowledge to draw
atoms of an element?
• Draw the atomic structure of the following
elements (remember to use the atomic number
and mass number to work out the particles in an
atom):
– Lithium (atomic number: 3; atomic mass: 7)
– Carbon (atomic number: 6; atomic mass: 12)
– Chlorine (atomic number: 17; atomic mass: 35)
• Complete the quiz at:
http://www.docbrown.info/page04/4_71atom/4_7
1atomQ.htm
The Atom Song