Log inSign up for FREE
Library

04.21.21 - Formulas and Names of Ionic Compounds

Last updated over 4 years ago
41 questions

Formulas and Names of Ionic Compounds

Objectives:
Students will:
  • write the name of an ionic compound when given the chemical formula of the compound.
  • write the chemical formula of an ionic compound when given the name of the compound.
Why?
Last unit, you learned about the different types of compounds that can be formed by the elements on the periodic table.

Today, we will learn about how different types of compounds are named, starting with ionic compounds.
1

How are you doing today? What do you need from me (your teacher) to do your best in class?

1

Match the element with the charge it has when it forms an ion.

Draggable itemCorresponding Item
Sodium
2+
Magnesium
1-
Chlorine
1+
1

Table salt, also known as sodium chloride, has the formula NaCl.

Road salt, which is magnesium chloride, has the formula MgCl2.

What do you notice about the formulas for these two salts? What is similar, and what is different?

Part 1: Writing Formulas of Ionic Compounds

Rules for writing the formula for an ionic compound
  1. Determine the charge on the metal when it forms a cation.
  2. Determine the charge of the nonmetal when it forms an ion.
  3. Determine the number of each ion needed to form an neutral compound.
  4. Write the element symbol of the metal first, followed by a subscript to show the number of cations in the compound.
  5. Write the element symbol of the nonmetal second, followed by a subscript to show the number of anions in the compound.
Note: Never write charges in the formula of a neutral ionic compound.

1

What is the chemical formula of sodium oxide?

1

What is the chemical formula of calcium chloride?

1

What is the chemical formula of gallium iodide?

For questions 7-15, determine the formula for the ionic compound listed.

Note: You will not be able to type subscripts so your formulas may look like this P4O6.
1

lithium bromide

1

magnesium oxide

1

aluminum fluoride

1

cesium sulfide

1

calcium nitride

1

strontium chloride

1

barium phosphide

1

chromium (III) phosphide

1

What do you think the Roman numeral in the name chromium (III) phosphide represents?

1

Why do you think chromium has roman numerals when it is in a name, but elements like barium and sodium do not?


* Remember, prefixes are only used when the compound is covalent. This is just a reminder of what the different roman numerals represent!


1

What is the chemical formula for iron (III) chloride?

1

What is the chemical formula for cadmium (I) nitride?

For questions 19-23, determine the formula for the ionic compound listed.

Note: You will not be able to type subscripts so your formulas may look like this: P4O6.
1

mercury (II) oxide

1

copper (I) chloride

1

nickel (I) oxide

1

lead (IV) sulfide

1

manganese (IV) oxide

1

A student is asked to write the chemical formula for lithium sulfate. What do you notice is different about this compound that the compounds you already know how to name?

Polyatomic ions are created when a group of atoms come to together to form a compound. In order for those group of atoms to successfully bond together, electrons either had to be lost or gain which results in a charge forming. The list of polyatomic ions below are the ones that will most often be used in class. You can later find these on Schoology in the Resources folder.



1

aluminum nitrate

1

copper (I) hydroxide

1

iron (II) phosphate

1

cobalt (II) phosphite

1

ammonium sulfate

1

Match the correct ionic compound name to the correct formula. You will also be asked to identify the which formulas are incorrect formula as well.

Draggable itemCorresponding Item
beryillium nitride
Cu2O
magnesium carbonate
CuO
copper (II) oxide
Be3N2
incorrect formula for beryillium nitride
Be2N3
incorrect formula for magnesium carbonate
MgCO3
incorrect formula for copper (II) oxide
MgC
Part 2: Naming Ionic Compounds Practice

Rules for naming ionic compounds:

1) Write the name of the cation (+ charged ion).
  • IF the cation is a transition metal (a metal located in the d block) you must include a Roman numeral in the name to indicate the charge of the metal.
2) Write the name of the anion.
  • IF the anion is a nonmetal changed the ending of the name to -ide. For example, chlorine becomes chloride.
  • IF the anion is a polyatomic ion, write the name of the polyatomic ion. Do not change the ending of its name.



Directions: For questions 31-41, write the the name of each of the ionic compounds below.
1

K2S

1

CuBr2

1

CoN

1

AlP

1

NaNO3

1

BaCl2

1

CaCO3

1

CuSO4

1

Fe2O3

1

Be3N2

1

Match the ionic formula to the correct name. Not all of the names will have a matching formula so choose wisely!

Draggable itemCorresponding Item

lead (IV) chloride

lead chloride
NaClO
sodium hypochlorite

sodium chloride oxide
PbCl4
cesium oxide
Zn(NO3)2
cesium (I) oxide

zinc (II) nitrate
Cs2O
zinc nitrate

zinc nitrogen oxide