Use a periodic table and your knowledge of the
element families to identify each element by name.
1. I am a member of the Carbon family with 14 electrons.
2. I am a member of the Alkaline Earth family and have 88
electrons.
3. I am a transition metals that is a liquid at room
temperature.
4. I am a transition metal with 79 protons.
5. I am a member of the Alkali Metal family with 20
neutrons.
The answers are …
1. I am a member of the Carbon family with 14
electrons.
Silicon
2. I am a member of the Alkaline Earth family
and have 88 electrons.
Radium
3. I am a transition metal that is a liquid at room
temperature.
Mercury
4. I am a transition metal with 79 protons.
Gold
5. I am a member of the Alkali Metal family with Potassium
20 neutrons.
Balancing Chemical Equations
What is a chemical equation?
Chemical equation - Describes a chemical change.
● Parts of an equation:
●
Reactant
Product
2Ag + H2S
Ag2S + H2
Reaction symbol
Reactants and Products
●
Reactant - The chemical(s) you start with before
the reaction.
●
●
Written on left side of equation.
Product - The new chemical(s) formed by the
reaction.
●
Right side of equation.
Subscripts and Coefficients
●
Subscript - shows how many atoms of an element
are in a molecule.
●
EX: H2O
● 2 atoms of hydrogen (H)
● 1 atom of oxygen (O)
●
Coefficient - shows how many molecules there are
of a particular chemical.
●
EX: 3 H2O
● Means there are 3 water molecules.
A Chemical Reaction
●
2H2 + O2 → 2H2O
Law of Conservation of Mass
●
In a chem. rxn, matter is neither created nor
destroyed.
●
●
In other words, the number and type of atoms going
INTO a rxn must be the same as the number and type
of atoms coming OUT.
If an equation obeys the Law of Conservation, it is
balanced.
An Unbalanced Equation
●
CH4 + O2 → CO2 + H2O
Reactant Side
1 carbon atom
4 hydrogen atoms
2 oxygen atoms
Product Side
1 carbon atom
2 hydrogen atoms
3 oxygen atoms
A Balanced Equation
●
CH4 + 2O2 → CO2 + 2H2O
Reactant Side
1 carbon atom
4 hydrogen atoms
4 oxygen atoms
Product Side
1 carbon atom
4 hydrogen atoms
4 oxygen atoms
Rules of the Game
●1. Matter cannot be created or destroyed.
●2. Subscripts cannot be added, removed, or changed.
●3. You can only change coefficients.
●4. Coefficients can only go in front of chem.
formulas...NEVER in the middle of a formula.
●A few extra tips:
●Try balancing big formulas first; save free elements for last.
●If the same polyatomic ion appears on both sides of the equation, it’s usually okay to
treat it as one unit.
●There is no one particular way to balance equations. Some equations are harder to
balance than others and might require some creativity to solve.
Balancing Equations
●
Balance the following equation by adjusting
coefficients.
N2 + 3H2 →
reactants
products
N
2
21
H
6
2
63
NH
2 3
Balancing Equations
●
Balance the following equation by adjusting
coefficients.
reactants
products
K
1
2
12
Cl
21
21
O
63
2
6
2 KClO3 → 2KCl + O
32
Balancing Equations
●
Balance the following equation:
●
2 C2H6 + 7 O2 → 4CO2 + 6H2O
Balancing Equations
●
Balance the following equation:
●
4Fe +3 O2 → 2 Fe2O3
Flame In A Bottle
Law of Conservation of Matter - Balancing equations
Flame In A Bottle
Law of Conservation of Matter - Balancing equations
Butane Bubbles
1. What did Mr. Wolfe create when he mixed the soap
and the water?(Use scientific Vocabulary)
2. What did Mr. Wolfe create when he mixed the soap,
water, and butane?(Use professional Language Here)
3. Were these two creations physical or chemical
changes?
4. What about the bubbles being lit on fire? Was that a
chemical or physical change?
5. Balance the equation for lighting the butane bubbles
on fire:
a. C4H10 +O2 -----> CO2 + H2O
Drawing Elements Practice - Next Week
Draw Elements 6-8 - bohr and lewis review +
label the following on each:
-Is it an Inert Gas?
-What Period is it in? (on the periodic table) -How
many electrons does it gain or lose to have 8 in
its Valence Shell?
- How Many electrons does it have in it’s valence
shell?
- How many energy levels does it have?