Date Period Name
CP Biology 2015-16

Use the following terms to fill in the blanks for questions 1-9: protons mass number neutrons energy levels nucleus symbol electrons atomic number
1) The large letter(s) that represent each element is called a symbol
2) The number of protons in the nucleus of an atom is the same as the a) _ atomic number __, and
b) electrons .
The periodic table is arranged in general order of increasing a) ___ atomic number __,
b) __ mass number ______ and, c) ___ # electrons (energy levels) ________.
3) Each element in the table has a different a) _ atomic number ____, b) # protons
c) symbol ________, and d) _ mass number _________.
Complete the diagram by labeling all the parts.
5) electron (valence)
6) nucleus
Made up of 7) protons and 8) neutrons
9) energy levels in the electron cloud
12) Complete the following table by placing a check in each box that makes the statement true:
Characteristic Proton Neutron Electron
Does not have an electrical charge
Found in the nucleus
Positively charged
Moves in energy levels
Negatively charged
Has nearly no mass
Added together to make the mass number or atomic mass (weight)
X
X
X
X
X
X
X
X
X
1

HW #2: Atomic Structure
You will become more familiar with the atomic structure of common elements by completing the chart below.
For each element, you have been given enough information to fill in all the blanks.
Element Symbol
He
Atomic
Number
2
Mass
Number
4
Number of
Protons
2
Numbers of
Neutrons
2
Number of
Electrons
2 Helium
Magnesium
Zinc
Bromine
Aluminum
Uranium
Sodium
Krypton
Calcium
Silver
Mg
Zn
Br
Al
U
Na
Kr
Ca
Ag
12
30
35
13
92
11
36
20
47
24
65
80
27
238
23
84
40
108
12
30
35
13
92
11
36
20
47
12
35
45
14
146
12
48
20
61
12
30
35
13
92
11
36
20
47

HW #3: Reactivity of Atoms (use your Notes Packet as a Word Bank)
In biology we are concerned about how atoms join each other to form molecules like hydrogen gas (H
2
), carbon dioxide (CO
2
) and glucose (C
6
H
12
O
6
). The tendency of atoms to bond with each other depends on how _ PROACTIVE / REACTIVE __ they are.
The reactivity or bonding ability of an atom depends upon the arrangement of electrons in the outermost energy levels.
1. If the outermost energy level is completely filled with electrons (no vacancies), the atom is said to be
____stable ____ and ___non reactive_____. It ( will / will not ) combine with other elements.
Examples _____noble gases-____He, Ne, Ar, Kr, Xe, Rn (in the far right hand column)_______________
2. If the outermost level is not completely filled with electrons(vacancies present), the atom is considered ______unstable______ and ___reactive_____. It ( will / will not ) combine with other elements.
1 1 1 1 R 1
13
6
13
6
3
4
Duet rule octet
5
4
R
R
X
4
11
10
8
11
10
8
1
8
6
7
0
2
R
NR
R
7 7 5 3 R
15 15 5 3 R
List the most common elements in living things:____C__, __H____, ___O___, ___N___, __P______
X
0
2
3
3

Are these elements reactive or non-reactive? ______REACTIVE____________
HW #4: Electrons and the Reactivity of Atoms
Directions: Place the answer to the following questions on the line provided.
___D___1. Energy levels are: a. the definite locations of electrons b. the charge of atoms c. the charge of protons d. the probable locations of electrons
__B___2. If an atom is reactive, how does it become stable? a. join a water molecule b. form bonds with other reactive atoms c. form energy levels with other subatomic particles d. join the nuclei of other atoms.
Directions: Smiley Cyrus was a student at Livingston High School. Below are her drawings of different atoms.
Check Smiley Cyrus’s atoms and correct any mistakes that she made.
* P=protons N=neutrons E= Electrons = electrons in energy levels
Aluminum Potassium Lithium
Add 3 e should be 19 e total 3 e -
13 P
14 E N
20 P
20 N
3 E
7 N
14 N in the nucleus, not 14 E
19 P not
20 P in the nucleus
3P & 4 N in the nucleus, not 7 E
Circle the atoms below that are reactive.
Al K Li
How many electrons will the following need to be stable? Write the number on the line provided.
Al ____5___ K ___7_____ Li ___7_____

1) Is one atom of carbon stable?________no________ Why or why not?___with only four electrons in its outer shell one carbon atom needs four more electrons to be stable (fulfill the octet rule)____________
2) What is the purpose of bonding? _In order to allow an atom to become stable (by sharing electrons to fill its vacancies – valence level)_________________________________________________
3) How many electrons will an atom of carbon share with another atom in order to become stable? __4___
4) List three different types of bonds that can form between atoms? a)____covalent____, b) ___ionic_________ and c) __hydrogen___________
5) A __ chemical formula ___ shows the types and numbers of atoms in a compound. For example, H
2
O indicates that one atom of oxygen has formed with two atoms of hydrogen.
The ____ subscript __ indicates how many atoms of the preceding element are needed in the final molecule.
A __ coefficient ____ indicates how many molecules of each compound are present. In order to determine the number of atoms in a formula with a coefficient, multiply the coefficient by the _subscript___. When the coefficient for a molecule is not indicated, that coefficient is the number one (example: CO
2
indicates one molecule of carbon dioxide). When the subscript for an atom is not indicated, that subscript is the number one
(example: the O in H
2
O).
Complete in the following chart:
Chemical Formula Numbers and types of atoms in the compound
H
2
O
CaCO
3
3H
2
O
4H
2
SO
4
Two hydrogen atoms and one oxygen atom.
One calcium atom, one carbon atom, 3 oxygen atoms
6 hydrogen atoms, three oxygen atom
8 hydrogen atoms, 4 sulfur atoms, 16 oxygen atoms
Directions for drawing structural formulas:
A structural formula is a drawing of the atoms in a compound and the number of bonds between atoms. The short lines in a structural formula represent a bond that has formed between two atoms. A single bond is represented by a single line (-). A double bond is shown with two lines (=). A triple bond would contain 3 lines
(

).
Example H
2
O or water :
In one water molecule, there _ 2 __ atom(s) of hydrogen and _ 1 ___ atom(s) of oxygen.
H =Hydrogen —Has one electron and one vacancy in the first energy level. So, it needs _ 1 __ bond(s) to be stable.
O =Oxygen —Has 2 electrons in the first level and 6 in the second level. So, it needs _ 2 _ bond(s) to be stable.
The only way to represent this is to draw:
H O H In this way, the two atoms of hydrogen are bonded with one atom of oxygen. The hydrogen atoms each have one bond and the oxygen atom has two bonds.

Try these examples:
Draw the structural formulas for the following compounds:
H
2
# bonds needed by hydrogen? _____1______
H H
O
2
# bonds needed by oxygen? ____2____
O O
N
2
# bonds needed by nitrogen ___3_____
CH
4
# bonds needed by carbon? ___4___ hydrogen? __1__
H
H C H
H
HCl
# bonds needed by hydrogen? ___1____ Cl? ___1__
H Cl
N N
HCN (Hydrogen cyanide)
H C N
H
2
O
PCl
3
# bonds needed by phosphorus? ___3___ Cl?____1__
Cl P Cl
Cl
H H
O

HW #6 Counting Atoms
Calculate how many atoms of each element are present in the following compounds.
1. NaHCO
3
Na-1
H -1
C -1
O -3
2. C
2
H
4
O
2
C-2
H-4
O-2
3. 3H
3
PO
4
4. 2H
2
SO
4
5. C
6
H
12
O
6
6. 4CaCO
3
H- 9
P-3
O-12
H-4
S-2
O-8
C-6
H-12
O-6
Ca-4
C-4
O-12
:
***7. Mg(OH)
2
Mg-1
O-2
H-2
***8. (NH
4
)
3
PO
4
N-3
H-12
P-1
O-4
7

HW #7: Recognizing Balanced Equations
EQUATION
A.
B.
H
2
+ O
2
--> H
2
O
2
H
2
O
2
--> H
2
O + O
2
C.
D.
E.
4Na + O
2
--> 2Na
2
O
N
2
+ H
2
--> NH
3
P
4
+ O
2
--> P
4
O
10
F.
G.
Fe + H
2
O --> Fe
3
O
4
+ H
2
C + 2H
2
--> CH
4
H. Na
2
SO
4
+ CaCl
2
--> CaSO
4
+ NaCl
I.
J.
C
2
H
6
+ O
2
--> CO
2
+ H
2
O
2Al
2
O
3
--> 4Al + 3O
2
BALANCED?
(Y/N)
Y
N
Y
N
Y
N
N
N
N
Y
7

HW #8: Balancing Equations
Answer the following questions. Use complete sentences when given one or more lines to respond.
1) What is the difference between reactants and products in a chemical equation?
_____reactants are the compounds that recombine____________________________
_____products are the result of the recombination of reactants____________________________
2) Which number indicates the number of atoms of each element in a molecule of a substance?
_____the subscript indicates the number of atoms of each element in a molecule of a substance _____
3) Which number indicates the number of molecules?
_____the coefficient indicates the number of molecules_________
4) Why must chemical equations always balance?
_____Chemical equations are the mathematical representation of chemical reactions, and matter (the atoms) is not created or destroyed in the reaction. Therefore the number of atoms does not change, even though they have been rearranged_______.
5) Based on the Law of Conservation of Matter , which of the following equations is balanced?

Put a check on the line provided if the equation is balanced.

Extension: If the equation is NOT balanced, then rewrite a correctly balanced equation below it.
_______ a) H
2
+ Cl
2
 2HCl 
_______ b) 2H
2
O
2
 2H
2
O + O
2

_______ c) N
2
+ H
2
 NH
3
N
2
+ 3 H
2
 2 NH
3
_______ d) Fe + 3O
2
 Fe
2
O
3
4 Fe + 3O
2
 2 Fe
2
O
3
_______ e) C
6
H
12
O
6
+ O
2
 CO
2
+ H
2
O C
6
H
12
O
6
+ 6 O
2
 6 CO
2
+ 6 H
2
O

*
ATOM