Download STAAR OBJ 3 Chemistry Review Notes

Objective 3
Structure and Properties of
Matter
MJH
Science YOU Need to Know!!!
Klawinsky
1
Structure
of the
Atom
2
Draw and Label this Model of an
Atom!!
electrons
(Negative)
protons
(Positive)
nucleus
neutrons
(Neutral)
NO charge!
3
Subatomic Particles
*Charges*
Protons Positive +
Neutrons Neutral o
Electrons Negative 4
Location of Subatomic Particles
Inside the
Nucleus:
Protons -- +
Neutrons o
LARGE!!!
98%
of
Outside the Nucleus:
Electrons
-
-
In energy levels
*Very, very, very small and
move very, very fast.
atom’s mass
5
Which subatomic particle has a positive charge?
Which subatomic particle has a negative charge?
Which subatomic particle has a neutral charge, 0?
Which particles are the largest and make up the mass of the
atom???
6
Charges!!!!
1.
If an atom has 25 protons, 27 neutrons and 25
electrons, what is the charge of its nucleus?
2.
If an atom has 25 protons, 27 neutrons and 25
electrons, what is the charge of the atom?
3.
If an atom has 19 protons, 21 neutrons and 22
electrons, what is the charge of the atom???
4.
If an atom has 32 protons, 34 neutrons and 33
electrons, what is the charge of the nucleus?
7
WHERE do I find the number of
protons, neutrons and electrons
found in an atom?!?!?!?!
It’s a
table......
8
The PERIODIC TABLE!!!
Use it!!!!!!!!
It has ALL you need to know about elements!
9
 USE IT!!!!
Periodic Table of the Elements:
Set up according to increasing ATOMIC NUMBER!!!
. . . which is the number of PROTONS!!!
WRITE THIS DOWN!!!
10
Information in Periodic Square
The periodic square for an element can tell you lots of information about that atom.
Atomic Number (Protons, +)
(Electrons, -)
Symbol
Atomic Mass
(Protons + Neutrons)
+
0
11
Na
22.99
11
P+
Atomic Number
Atomic number = #
P+
of protons =
(number at the top)
(also equals # of
electrons)
12
BIG
number
MASSIVE!!
Atomic Mass
P + N = Mass
(Found in the nucleus of an atom.)
Do you remember………..
13
SO, to Calculate Number of
Neutrons. . .
Subtract atomic number from the atomic mass
(p+)
and
(p + n)
Atomic Number
The two
numbers
in the
box!!!!
17
Cl
35
Atomic Mass
Chlorine
14
SO, to Calculate Number of
Neutrons. . .

Subtract atomic mass and atomic number
(the two numbers in the box)
EXAMPLE
Atomic Number
Symbol
Atomic Mass
11
Na
22.99
TAKS Need to Know
23
- 11
12
Number of neutrons
15
Now You Try!!
3
How many
neutrons?
Li
6.941
Lithium
16
Answer:
7
- 3
4
--atomic mass
--atomic number
NUMBER of NEUTRONS
How many
protons?
How many
electrons?
17
18
Practice!!

Complete the chart on
your paper using the
Periodic Table of the
Elements.
19
Element
Chlorine
Protons
17
Neutrons
18
Electrons
17
Iron
26
30
26
Magnesium
12
12
12
Lead
82
125
82
20
EVEN MORE about the
Periodic Table…
Elements with SIMILAR PROPERTIES fall into the SAME GROUP in the periodic table
SO: If I am chlorine (Cl) what elements will have similar properties to me??
IF I am potassium (K) what elements will have similar properties to me??
**NOTE: Elements in the same group/family are in the columns!!!!!
21
GROUP # above the table!!
number of valence electrons -- similar properties
PERIOD # to the left of the table!!
number of energy levels around nucleus
22
What is a valence electron??
23
Electrons in the outermost level
3
VALENCE
ELECTRON
Li
6.941
8e1 e-
Lithium
3P+
4No
22e-e-
24
What makes one element more
reactive than another??

The FEWER valence electrons an element
has, the MORE reactive it is.

REACTIVITY decreases as you read across
the Periodic Table from left to right.
Let’s take a look.
25
Which group
has the
greatest
reactivity?
(Elements become LESS REACTIVE as you move across the table!!)
26
Electrons:
Arranged in energy levels
(2,8,18,32)

The part of the atom
involved in chemical
reactions
18e-e32
8e- e8 (18)
8e8 e-


Why do atoms react with
each other?
The atom reacts in order
to have a FULL outer
energy level
P+
No
22e-e-
Group/Period Practice
Use your
periodic
table.
Find the correct number of valence electrons and
energy levels for the following elements.
Element
# of Valence Electrons
(Group #)
# of Energy Levels
(Period #)
Ca --- Calcium
Na --- Sodium
Sn --- Tin
28
F
Na
Ca
Sn
Element
# of Valence
Electrons
(Group #)
(TOP)
# of Energy
Levels
(Period #)
(LEFT)
Ca --- Calcium
2
4
Na --- Sodium
1
3
Sn --- Tin
4
5
29
Metals, Nonmetals and
Metalloids!!
30
The stair-step line separates the
elements into metals and nonmetals.
31
Chemical Formula

letters and numbers that represent a chemical
compound
BUT….what does it all mean??????????????
32
Chemical Formula:
Compound
NaCl
Number of Number
elements in of atoms
compound
per
element
2: Na & Cl
Fe2O3
2: Fe & O
2H2SO4
3: H, S, O
1 Na,
1 Cl
2 Fe,
3 O
4 H, 2 S,
8 O
TOTAL
number
of atoms
in
compound
2
5
14
EWWWW!! What is that
called????
34
. . . Coefficient!!!

Multiply this number by all subscripts in the
chemical formula.
(Calculate # of atoms of each element.)
2H2SO4
4CaCl4
PRACTICE!!
35
Chemical Equations
“YIELDS”
(produces)
Reactants are the
substances you
start with.
Products are
produced.
36
The Law of Conservation of Matter
Matter is neither created nor destroyed
it is only changed….rearranged.
This reminds us that ALL chemical equations
should be BALANCED.
37
2Ag
+
H2S
Atoms in reactants:
2 Ag
2H
1S
Ag2S
+
H2
Atoms in products:
2 Ag
2H
1S
38
Balance the equations in your
packet.
39
1.
N2 + 3H2
2NH3
Answer:
1.
REACTANTS
N2 + 3H2
2N
6H
PRODUCT
2NH3
2 N
6 H
BALANCED!!
2.
H2O2
H20
+ O2
42
Answer:
2.
REACTANT
H2O2
2H
2O
PRODUCTS
H20
+ O2
2 H
3 O
UNBALANCED!
3.
Fe + Cl2
FeCl3
44
Answer:
3.
Fe + Cl2
1 Fe
2 Cl
FeCl3
1 Fe
3 Cl
UNBALANCED!
45
Elements vs Compounds
Look at this equation.
N2 + 3H2
2NH3
Which reactant or product is an element?
Why?
Which reactant or product is a compound?
Why?
46
47