building atoms. the periodic table will help you! the pte is an arrangement of the elements into...
TRANSCRIPT
Building Atoms
The Periodic Table Will Help You!The PTE is an arrangement of the elements into groups that have similar properties.
The
horiz
onta
l row
s ar
e pe
riods
. The columns are groups or families.
A closer look
Each square looks like this:
O8
15.999Oxygen
Atomic Number = Protons OR Electrons
Average atomic mass
Symbol
Drawing the nucleus
Draw the nucleus of an oxygen-16 atom:
O8
15.999Oxygen
++
+++
+
+
+
We often replace the picture with: 8p/8n
Protons = 8Neutrons = 16 - 8 = 8
What about the electrons?
The electrons will go on orbits (energy levels): 8p/8n
O8
15.999Oxygen
Atomic Number = Protons OR Electrons
Find the element in the PTE
1 orbit2 orbits3 orbits4 orbits
5 orbits6 orbits
Draw the correct number of orbits.
O
let’s put the electrons in
8p/8n
Rules!
The first orbit holds up to 2 electrons.The second orbit holds up to 8 electrons.
The order you put them in matters.
In general
1 2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Rules!
The 1st orbit holds up to 2 electrons.The 2nd orbit holds up to 8 electrons.The 3rd orbit holds up to 8 electronsThe 4th & 5th each hold up to 18 electrons
Lets try Carbon!
Draw a carbon-12 atomHow many orbits?
C6
12.011Carbon
2
6p/6n
Phosphorus
Draw a phosphorus-31 atomHow many orbits?
15p/16n
3
Valence Electrons
Valence electrons are electrons in the outermost orbit of an atom.
This carbon atom has 4 valence electrons.
The inside orbit is filled.
6p/6n
Another wayYou can also figure out how many valence electrons are in an atom by looking at your periodic table:
IGNORE THESE GUYS!
1 Va
lenc
e el
ectr
on
2 Va
lenc
e el
ectr
ons
3 Va
lenc
e el
ectr
ons
4 Va
lenc
e el
ectr
ons
5 Va
lenc
e el
ectr
ons
6 Va
lenc
e el
ectr
ons
7 Va
lenc
e el
ectr
ons
8 Va
lenc
e el
ectr
ons
2
Helium is a special exception-it has only 2!