Writing Formulas and Names for Ionic and Covalent Compounds

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Science · Chemistry
SP-CHEM-006  ·  Free to print and use in your classroom  ·  substituteplans.com
Page 2
Writing Formulas and Names for Ionic and
Covalent Compounds
Science · Chemistry · Grades 9-11 · 50 minutes
Time needed
50 minutes (one class period)
Prep
Copy the 2-page worksheet (one per student).
Technology
None. A basic calculator is optional.
Student
independence
High. Students work alone, then check with a partner.
Copies to make
One 2-page worksheet per student
Materials
Pencils, Worksheet
Goal for today: Students will write correct formulas and names for ionic compounds using ion charges and for simple
covalent compounds using Greek prefixes.
Before the bell
☐ Copy the worksheet, one per student (2 pages).
☐ Write on the board: The positive charges must cancel the negative charges. Use parentheses around a
polyatomic ion if you need more than one.
☐ Keep the answer key on your desk. Every ion and prefix needed is printed on the worksheet.
Say this to start
Good morning! Today in chemistry you will practice the naming system for compounds. It works like a puzzle: match
positive and negative ions so the charges cancel out, then write the formula. The worksheet has a table of every ion
you need. Please work on your own and use the table whenever you are unsure.


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Page 3
Run of show
Minutes
What you do
What students do
0–5
Take attendance. Hand out the worksheet. Ask students to
study the ion table and the prefix list.
Read the tables silently.
5–13
Read this example aloud: Magnesium is Mg²⁺ and chloride
is Cl⁻. One Mg²⁺ needs two Cl⁻ to cancel. The formula is
MgCl₂. Then: calcium hydroxide uses Ca²⁺ and OH⁻, so we
need two hydroxides: Ca(OH)₂.
Follow along and copy both examples into
the margin.
13–25
Tell students to complete Part A (questions 1–6). Tell them
to check each formula by adding up the charges.
Write formulas from names and check that
the total charge is zero.
25–38
Tell students to complete Part B (questions 7–12), writing
names from formulas. Remind them that iron and copper
need a Roman numeral for the charge.
Name each compound, including Roman
numerals where needed.
38–47
Tell students to complete Part C (questions 13–16). Then
read the key aloud. Students check and correct their work.
Name the covalent compounds using
prefixes and check answers.
47–50
Collect the worksheets and put them in a stack for the
teacher.
Hand in the worksheet.
If things go wrong
• If students ask why Ca(OH)₂ has parentheses, tell them the parentheses show that the whole OH group
repeats twice.
• If students are not sure about Roman numerals, point to the table: the number in parentheses is the charge
on the metal.
• If students forget prefixes, point to the prefix list. Mono is not used for the first element.
• If the class finishes early, use the early finisher list.
Early finishers
• Write the formula and name for a compound of Ca²⁺ and O²⁻ on the back.
• Make up one compound from the ion table that is not on the worksheet. Write its formula and name and swap
with a neighbor to check.
Support and challenge
• Support: Complete questions 1–4, 7–9 and 13–14. Use the examples on the board as models.
• Challenge: Write the formula for aluminum sulfate and explain how you decided on the subscripts. Show it on
the back.


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Science · Chemistry
SP-CHEM-006  ·  Free to print and use in your classroom  ·  substituteplans.com
Page 4
Notes for the teacher (you fill this in)
Jot a few lines before you leave. A full Daily Sub Report is in the free Sub Survival Kit at SubstitutePlans.com.
How far the class got / what to pick up next:
Students who were especially helpful:
Anything the teacher should know: