The Nomenclature of Inorganic Compounds: The Periodic Table of Elements

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Discussion no. 2
The Nomenclature of Inorganic Compounds
Discussion no. 3
The Periodic Table of Elements

Sta. Maria, Yza
Suaco, Trisha Marie T.
Teves, Joan Marie
Vale, Kate
IN-9 Group 9

I. Introduction
Representing molecules as images allows us to impart a great deal of information concerning molecular structure. But these molecules can also be named, and there are occasions when this is more convenient than drawing a picture. In the early days of chemistry, the list of known compounds was short that chemists could memorise the names of all of them. Some of the unique names given by chemists in the early days were salt, cinnabar and laughing gas – names which tells us nothing about what the compound is. New compounds were often named by their origin of place, their discoverer, their physical appearance or properties. Today, more than 20 million compounds are known and thousands more are synthesized each year. Chemists consequently need systematic procedures for naming chemical compounds. The International Union of Pure and Applied Chemistry (IUPAC) has established uniform guidelines for naming various types of chemical substances. II. Discussion

The Nomenclature of Inorganic Compounds
Objectives: To be familiar with the different rules governing the formulation of a compound’s chemical name as well as its formula.
Chemical compounds are divided into two groups and these are: Inorganic and Organic. Organic compounds are composed of principally carbon, hydrogen and oxygen (these are the compounds of life) while all other compounds are called inorganic compounds. Classification of Compounds:

A. Binary Compounds
1. Metal and Non-metal
Inorganic compounds composed of just two elements, metal cations (positive ions) and non-metal anions (negative ions). These are referred to as metal-nonmetal binary compounds. There are two types of metals, some metals form cations with only one charge (e.g.Na+, K+) while other cations form two or more charges (e.g.Ca2+, Al3+). Metals with Fixed Oxidation Number

Group IIA ( Alkaline Earth Metals) (Zn &Cd- transition metals) Group IIA ( Alkaline Earth Metals) (Zn &Cd- transition metals) Group IA (Alkali Metals) (Ag- transition metals)
Group IA (Alkali Metals) (Ag- transition metals)

Cations| Name|
Li+| Lithium|
Na+| Sodium|
K+| Potassium|
Rb+| Rubidium|
Cs+| Cesium|
Ag+| Silver|
Cations| Name|
Be2+| Beryllium|
Mg2+| Magnesium|
Ca2+| Calcium|
Ba2+| Barium|
Zn2+| Zinc|
Cd2+| Cadmiun|

Cations| Name|
Al3+| Aluminum|
Group IIIA
Group IIIA

GUIDELINES FOR BINARY IONIC COMPOUNDS
1. The cation is listed first before the anion
2. The cation-anion must give a net charge of zero
3. The ratio is always expressed by the smallest whole numbers 4. The unchanged name of the metal is used.
5. The name of the anion includes only the English root plus –ide Criss-Cross Method- The numerical value of the charge on the cation becomes the subscript on the anion and vice versa. Example| Criss-Cross Method|

Sodium Sulfide| Na+ S2- = Na2S| 2(+1)+(-2)= 0|
Aluminum Chloride| Al3+ Cl- = AlCl3| (+3)+3(-1)= 0| Example:

Metals with Varied Oxidation Number

* 1.2.1 Stock Method

Stock Method - the name of the metal is followed immediately by a Roman Numeral in parentheses to indicate the charge of the ion. (e.g. Iron (III), Arsenic (IV)) .

Using The Stock Method
In using the Stock Method, one will use a simple algebra equation to determine the charge on the metal and the proper roman numeral to use for more complex compounds. [(Number of Metal Cations)X(charge on metal)] + [(number of non-metal cations)X(-charge on nonmetal)] = 0 Example:

1.) Name of the compound Fe2S3
[(2x(Fe Charge)] + [3x (S charge)] = 0
2 Fe + (3 x -2)= 0
2 Fe = +6
Fe= +3 (III)
The compound is therefore Iron (III) Sulfide
2.) Finding the formula...
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