1/6/09
Post date: Jan 06, 2009 2:4:40 AM
Bell Activity: Where have you seen Roman numerals used? List the first 10 Roman numerals.
Roman Numerals
1 = I
2 = II
3 = III
4 = IV
5 = V
6 = VI
7 = VII
8 = VIII
9 = IX
10 = X
Some elements (transition metals) form more than one type of cation
With these elements, we must include some way to show which ion we're talking about
We do this with roman numerals to show the charge of the ion
Example: Iron, Fe
Iron can give up either 2 or 3 electrons, so it will have either a 2+ or 3+ charge
The Iron ion with a 2+ charge is written as Iron (II) ion
The Iron ion with a 3+ charge is written as Iron (III) ion
Below are the possible charges of the transition metals
Writing formulas for ionic compounds
Start with a cation and an anion
Write the symbols (with charges) for each ion
Put them next to each other, with the cation first
Cross the charges and bring them down to subscript to show how many of each ion is involved
Example: Hydrogen Chloride
Example: Iron (III) oxide
Naming ionic compounds assignment
Given the following compound names, write the formula of each ionic compound
Sodium chloride
Hydrogen fluoride
Copper (II) oxide
Potassium bromide
Magnesium phosphide
Naming ionic compounds
compounds consist of an anion and a cation
Write the name of the anion and the cation
Put the two together, with the cation's name first
If the cation is a transition metal
Find the charge on that transition metal by reversing the cross you did in the last step. If there is one of each type of ion in the compound, the transition metal has the same number (but opposite sign) as the anion.
Use roman numerals to indicate which charge that cation has
Naming ionic compounds assignment
Given the following formulas, write the name of each ionic compound
LiCl
BeF2
Ca2C
HBr
Fe2O3