A covalent bond is a shared pair of electrons. The bond between the two atoms of any diatomic gas, such as chlorine gas, Cl2, is certainly equally shared.
The chemical formula of a compound represents this combination. The single unit can be molecules or groupings of ions. Every molecule, ion and ionic compound has a name. A system of naming chemical substances is called a chemical nomenclature.
There are various ways of naming substances. The systematic naming is the most useful. A systematic system follows a set of rules.
The set of rules will give one name for one formula. For example, the name sulphur oxide is not a systematic name because both SO2 and SO3 molecules exist. The systematic name sulphur VI oxide, however, can only mean SO3.
The systematic naming has the added advantage of giving other information about the compound. This includes oxidation state and number of atomscombining to form the compound. Trivial or common names are old, traditional names.
They are not necessarily based on any rules.
As an example, the common name for the formula H2SO4 is sulphuric acid and the systematic name is tetraoxosulphate VI acid. However, the IUPAC system still includes some trivial names which have been found to be simple and useful.
Inorganic compounds are mainly compounds of metals and non-metals with the exception of carbon. The naming of inorganic Compounds relies on oxidation numbers.
For example, in hydrogen chloride molecule, chlorine more electronegative than hydrogen. Therefore, the shared pair is counted towards chlorine atom as shown below: As a result of this, chlorine gets one extra electron and acquires a unit negative charge.
Hence, oxidation number of chlorine is On the other hand, hydrogen atom without electron has a unit positive charge. It may be noted that electrons shared between two similar atoms are divided equally between the sharing atoms. For example, in chlorine molecule Cl2the electron pair is equally shared between the chlorine atoms.
Therefore, one electron is counted with each chlorine atom as shown below: Now, there is no net charge on each atom of chlorine. In other words, oxidation number of chlorine in Cl2 molecule is zero. Thus, atoms can have positive, zero or negative values of oxidation numbers depending upon their state of combination.
Now since it is not always possible to remember or make out easily in a compound or ion which element is more electronegative than the other, therefore, a set of rules have been formulated to determine the oxidation number.
If two or more than two atoms of an element are present in the molecule ion, the oxidation number of the atom of the element will than be average of all the atoms at that element.
All elements have oxidation numbers in whatever state they occur. Some common ones are given in Table Arabic numerals are used in the algebraic exercises to determine oxidation numbers, e. A combination of the knowledge of oxidation numbers, and how to indicate the number of atoms, ions or radicals, enables the correct formula of a compound to be written.
The charge on a species is written as a right superscript followed by its positive or negative sign. These rules have been formulated on the basis of the assumption that electrons in a covalent bond belong entirely to the more electronegative atom.
The oxidation number of the element in the free or elementary state is always zero-irrespective its allotropic form. The oxidation number of fluorine is always -1 in all its compounds. Other halogens Cl, Br and I also have an oxidation number of -1, when they occur as halide ions in their compounds.
However, in oxoacids and oxoanions they have positive oxidation numbers. Oxygen is assigned oxidation number -2 in most of its compounds, however; in peroxides which contain linkage like H2O 2, BaO2, Na2O 2, etc.
In accordance with the principle of conservation of charge, the algebraic sum of the oxidation numbers of all the atoms in molecule is zero.Naming Acids and Bases Acid names are based on the anion they form when dissolved in water; base names follow the rules for ionic, organic, .
6. APPLY CHEMISTRY TO EVERYDAY LIFE: The study of science as a mental exercise is not very useful. Applying science knowledge to practical everyday problems is the main purpose in studying any science; chemistry, physics, biology, or . Worksheet I used for higher ability year 7/8 to name salts made in neutralisation reactions.
Can be used for older students as a starter/recap or edited to have more/less support. Binary ionic compounds are composed of two elements.. The first element is a metal.
The second element is a non metal.. An "ide" suffix is used to indicate that compound has been formed between the elements.. Chemical Formula of Binary Ionic Compounds. Naming and Writing Formulas for Acids!
•1st –determine if the compound is an acid –a. If you are given a formula, is the first element hydrogen?
If yes, . Naming Acids Acids -For simplicity, the acids that we will be concerned with naming are really just a special class of ionic compounds where the cation is always H +. So if the formula has hydrogen written first, then this usually indicates that the hydrogen is an H + cation and that the compound is an acid.