Atomic Theory 2000

Draw - groups of 4 - your picture of a atom  on newsprint

I.  The whole universe is made of different kinds of atoms -elements

II.  There are 92 naturally occurring elements  [chart]

·        There are 110 total elements

 

III. There are 3 parts to atoms

                       

	charge	mass	location
proton	+	1	nucleus
electron	-	1/1837 or 0	outer
neutron	neutral	1	nucleus

 

IV.  Atomic Number

·        numbers them from lightest to heaviest

·        equals the number of protons!

           

Next: mass of each   proton = 1 amu    neutron = 1    electron = 0

           

V. Atomic Mass is number of protons plus number of neutrons

           

	Mass	# of +	# of neutrons
H	1	1	0
He	4	2	2
Li	7	3	4
B	11	5	6

 

VI.  Electrons

·        If neutral, # of protons equals # of electrons

 

 

+	-	n

     VII. Practice these atoms                 (make table of  +, neutrons, -)

             ₂He⁴    ₄Be⁹    ₁₅P³¹   ₁₆S³²

 

+	-	n
2	2	2

 

+	-	n
4	4	5

 

+	-	n
15	15	16

 

+	-	n
16	16	16

 

VIII. Energy Levels

·        electrons whirl in zones called shells

·        they are likely to be in many places so they are called an electron cloud

·        each shell can hold only so many

·        Rule One:  1st shell holds 2

·        Rule Two:  2nd holds 8

·        Rule Three: Last shell holds 8 

                                     (it gets more complicated but that is the idea)

             

IX.  Full shells are inert    - Stable

             

X.   Isotopes  {complete!} + Drawings: ₁H¹ ₁H² ₁H³ ₂He⁴ ₃Li⁷ ₁₁Na²³

+	-	n
1	1	0

 

 

 

one or two "extra" electrons are metals

short by 1 electron are halogens

 

Drawing of the first four examples are shown above

 

10/11/00