Transcript Chemistry Review - Solon City Schools

Chemistry Review
Do you remember anything
from science investigations?
Atomic Structure
Nucleus- center of an atom
-contains protons - which are positive
-contains neutrons- which are neutral
 Electrons (which are negative) surround
the nucleus in energy levels
1st energy level = holds 2e
2nd energy level = holds 8e
3rd energy level = holds 18e
4th energy level = holds 32e

Bohr Model of Atom
Periodic Table tidbits
Period table organization – organized by
increasing atomic number
 Split into metals (left side of stair step line)
and nonmetals (right side of stair step line)
 Groups – vertical columns (#1-18)
 Periods – horizontal rows (#1-7)

More Chemistry tidbits
Atomic number = number of protons
 Mass number = # protons + # neutrons
 #Neutrons = mass number - # protons
 # protons = # electrons
 REMEMBER “APE”= ATOMIC NUMBER,
#PROTONS, #ELECTRONS WILL EQUAL
EACH OTHER IN A NEUTRAL ATOM

Isotopes (I said isotope you dope!)
Isotopes are different atoms of the same
element that contain the same number of
protons but different number of neutrons.
 Examples

Cl-35
vs.
Cl-37
17P
17P
18N
20N

Chemical Bonding
Remember atoms bond with one another
in order to become stable (need to get 8
electrons in outer ring)
 Exception- hydrogen only needs 2
electrons in outer ring to be stable
 Bonds are forces of attraction between
elements
 Involves bonding of valence electrons
(electrons in outermost shell)

Lewis Dot Structures
 Lewis
dot diagrams- display the
number of valence electrons
(outermost electrons) around the
element symbol
 Used to show how atoms of different
elements bond and form compounds
 Hint- use group number to find
valence electrons
Electron configurations

Lewis Dot Diagrams

Types of Bonds
bond – sharing of electrons
-occurs between 2 nonmetals
-types- single (shares 1 e)
double (shares 2 e)
triple (shares 3 e)
*REMEMBER HYDROGEN IS A
NONMETAL AND FORMS
 Covalent
Covalent bonds
H2-hydrogen gas-sharing of electrons
Types of Bonds
 Ionic
bond- one atom gives an
electron to another atom (remember
it’s the losing and gaining of
electrons)
 Involves forming ions (have positive
and negative charges)
 Occurs between a metal and a
nonmetal
Bond Diagrams
Covalent bonds-remember they share
electrons
 Ex. F2

Bond Diagrams
 Ionic
Bond-lose & gain
electrons
 Ex. NaCl
Ionic bond Lewis dot diagram

NaCl- sodium chloride
Covalent Bond Lewis dot structure

HF-hydrogen fluoride
What is inside the nucleus of an
atom?
Protons and electrons
Electrons and neutrons
Protons only
Protons and neutrons
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20
What are the dots in Lewis dot
diagrams?
Number of protons
Number of neutrons
Number of valence
electrons
Number of inner
shell electrons
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20
An ionic bond is between
1 metal and 1
nonmetal
2 nonmetals
2 metals
None of the above
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20
A covalent bond is between
2 metals
1 metal and 1
nonmetal
2 nonmetals
3 metals
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20
How do you find the number of
valence electrons to draw for a
Lewis dot diagram
Look at the atomic
number
Look at the mass
number
Look at the number
of neutrons
Look at the group
number
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20