Writing the Word Equation to Reactions
Vocabulary
reactants
product
valance
decompose
+
Cation
Sodium
(Na)
Cation
Anion
+
-
anion
C h l o r i ne
(Cl)
Sodium Chloride
+
Reactants
Arrow
“combines with”
“added to”
“reacts with”
“combusts”
“to form”
“to make”
“produces”
Product
Sodium reacts with chlorine to form sodium chloride. Write the word equation for the
reaction.
Classwork
Write the word equation for the following reactions:
1) Copper sulphate reacts with sodium hydroxide to form cupper hydroxide and sodium sulphate.
2) Iron reacts with chlorine to form iron chloride.
3) Hydrochloric acid reacts with sodium carbonate to produce sodium chloride as well as water and carbon
dioxide.
*
4) Copper carbonate decomposes when heated to form copper oxide and carbon dioxide.
Hint: Decomposes means breaking down. So, the chemical equation will be reversed.
* = Challenge question
Criss-cross Method
Criss-cross method is a way to write the formulas of Ionic compounds.
Ionic Compound: cation + anion, a metal and a non-metal
Rules for naming:
Cation is written and named 1st + Anion is written 2nd, but change the ending to “-ide”
How do you know if it is a positive ion or negative ion? The periodic table
will tell you. Look below, the positive ions are in these columns (groups).
B C
Look below, the negative ions are in these columns (groups).
B C
Refer to the periodic table above while reading the examples below. Find the element’s cations OR
anions. Find the element’s valence number. Do the examples below match?
Classwork (continued)
1. Use the periodic table above to find the positive (cation) charge & number OR negative
(anion) charge & number.
2.
Use the criss-cross method to “form” their “product”. Write your answer in the space
provided or in your notebook.
Calcium (Ca) + Sulfur (S)
Potassium (K) + Oxygen (O)
Magnesium (Mg) + Oxygen (O)
Sodium (Na) + Oxygen (O)
Boron (B) + Phosphorus (P)
Sodium (Na) + Iodine (I)
Calcium (Ca) + Oxygen (O)
Boron (B) + Nitrogen (N)
Sodium (Na) + Phosphorus (P)
Potassium (K) + Nitrogen (N)