Skip to content




COVALENT BONDING As well as achieving noble gas structures by transferring electrons from one atom to another as in ionic bonding, it is also possible for atoms to reach these stable structures by sharing electrons to give covalent bonds.   Depending on the number of electron pairs shared between atoms which participate in bonding, covalent bonds are classified as follows: Some simple covalent molecules   Chlorine For example, two chlorine atoms could both achieve stable structures by sharing their single unpaired electron as in the diagram. The fact that one chlorine has been drawn with electrons marked as crosses and the other as dots is simply to show where all the electrons come from. In reality there is no difference between them. The two chlorine atoms are said to be joined by a covalent bond. The reason that the two chlorine atoms stick together is that the shared pair of… Read More »COVALENT BONDING – SINGLE BONDS



Occurrence Hydrogen does not occur free in nature. It occurs as Water and in Petroleum. School laboratory Preparation Procedure Put Zinc granules in a round/flat/conical flask. Add dilute sulphuric(VI) /Hydrochloric acid. Add about 3cm3 of copper(II)sulphate(VI) solution. Collect the gas produced over water as in the set up below. Discard the first gas jar. Collect several gas jar.   Observation/Explanation Zinc reacts with dilute sulphuric(VI)/hydrochloric acid to form a salt and produce hydrogen gas. When the acid comes into contact with the metal, there is rapid effervescence/ bubbles /fizzing are produced and a colourless gas is produced that is collected: (i) Over water because it is insoluble in water (ii) Through downward displacement of air/upward delivery because it is less dense than air. The first gas jar is impure. It contains air that was present in the apparatus. Copper(II)sulphate(VI)solution act as catalyst. (a) Chemical equation (a) Zinc + Hydrochloric acid ->Zinc… Read More »HYDROGEN



WATER AND HYDROGEN Hydrogen is the simplest element. It is the first element in the periodic table, and it is placed in Group I of the periodic table.   Hydrogen Occurrence Hydrogen is the lightest element and the most abundant element in the universe. Hydrogen occurs naturally as a mixture of the three isotopes: Protium, H, Deuterium, D, (which is also called Heavy Hydrogen) and Tritium, T.   Preparation of Hydrogen by the Action of Metals The alkali metals, lithium, sodium, and potassium react violently with water at the ordinary temperature, yielding hydrogen. 2 Li + 2 H2O H2 + 2 LiOH Calcium reacts with water more slowly unless the water is hot, when the action is more vigorous. Ca + 2 H2O H2 + Ca(OH)2   Preparation of Hydrogen from Action of Acids Hydrogen is prepared in the laboratory by the action of acids on metals. Dilute sulphuric acid containing 1… Read More »WATER AND HYDROGEN

School Portal NG
error: Content is protected !!