Presentation on theme: " How are ionic compounds named? What do the numerical prefixes used in naming covalent compounds tell you? What does a compound´s empirical formula."— Presentation transcript:
How are ionic compounds named? What do the numerical prefixes used in naming covalent compounds tell you? What does a compound´s empirical formula indicate?
Empirical formula Anion Molecular formula Cation
The names of ionic compounds consist of the names of the ions that make up the compounds Name of cations include the elements of which they are composed Ion name and symbol Cesium ion, Cs+ Lithium ion, Li+ Sodium ion, Na+ Barium ion, Ba2+ Calcium ion, Ca2+ Aluminum ion, Al3+ Ion charge1+2+3+
Names of anions are altered names of elements NaF: is made of sodium ions, Na+, and fluoride ions, F-. Therefore, its name is sodium fluoride An ionic compound must have a total charge of zero If an ionic compound is made up of ions that have different charges, the ratio will not be 1:1 For calcium fluoride to have a total charge of zero, there must be two fluoride ions for every calcium ion
Some cation names must show their charge The charge of the iron cation in Fe 2 O 3 is different from the charge of the iron cation in FeO. In cases such as this, the cation name must be followed by a Roman numeral in parentheses that shows the cation’s charge. Fe 2 O 3 is made of Fe 3+ ions, so it is named iron (III) oxide. FeO is made of Fe 2+ ions, so it is named iron (II) oxide.
Determine the charge of a transition metal cation How can you tell that the iron ion in Fe 2 O 3 has a charge of 3+? Write formulas for ionic compound using names You can find the charge of each ion in a compound if you are given the compound’s formula. You can find the formula for a compound if you are given the compound’s name
Math Skills: Writing Ionic Formulas Go to go.hrw.com and enter keyword HK8MPgo.hrw.com
For covalent compounds or two elements, numerical prefixes tell how many atoms of each element are in the molecule Numerical prefixes are used to name covalent compounds of two elements If there is only one atom of the first element, the name does not get a prefix The element farther to the right in the periodic table is named second and ends in –ide One boron atom and three fluorine atoms make up boron trifluoride, BF 3
An empirical formula tells us the smallest whole-number ratio of atoms that are in a compound Different compounds can have same empirical formula Molecular formulas are determined from empirical formulas Masses can be used to determine empirical formulas
Empirical formula: the composition of a compound in terms of the relative number and kinds of atoms in the simplest ratio Molecular formula: a chemical formula that shows the number and kinds of atoms in a molecule, but not the arrengement of atoms
Math Skills: Finding Empirical Formulas Go to go.hrw.com and enter keyword HK8MPgo.hrw.com