Secondary Catalogue
Chemistry
The Modern Periodic Table
Periodic Classification of Elements
The elements in the Periodic Table are roughly divided into metals, metalloids and non - metals. There are seven periods in the Periodic Table. The vertical columns in a Periodic Table are called groups and there are 18 groups in the Periodic Table.
Rusting and Its Prevention
Rusting damages things made of iron, making the structures weak. Rusting can be prevented by the use of some methods.
Solids
Solid is that state of matter which retains a fixed shape and volume. The particles in solids are closely packed and hence the interparticle forces are the strongest in it. Solids cannot be compressed and posses rigidity.
Characteristics of Groups: Valence Electrons and Valency
Periodic Classification of Elements
The groups in the Periodic Table are arranged vertically. There are 18 groups in the Periodic Table. All the elements in one group have the same electronic configuration and hence the same number of valence electrons and the same valency.
Combination Reaction
A combination reaction is a reaction, in which two or more elements or compounds combine together to form a single compound. For example, magnesium burns completely on heating, leaving behind a powdery white ash of magnesium oxide.
Physical Properties of Metals
Metals are generally solid, hard and strong, have a metallic lustre and high melting and boiling points. Metals are also malleable, ductile, and good conductors of heat and electricity.
Expansion in Solids
Solids expand on heating and contract on cooling. Different solids expand by different amounts for the same rise in temperature.
The Importance of pH in the Human Body
The pH in the human body tells about the value of the acidity or basicity of an aqueous solution. Acidity produced in the stomach, due to overeating, can be reduced by having an antacid, like the syrup milk of magnesia.
Factors Affecting Evaporation of Liquids
Liquids changes into vapour by the process of evaporation. The factors that affect the rate of evaporation of liquids are temperature, surface area, wind speed, and humidity.
Electroplating
Chemical Effects of Electric Current
The process by which a thin layer of a metal is coated on a different metal object by means of electrolysis is called electroplating. Electroplating is done mainly to prevent the corrosion of the inner metal and to give it an attractive look.
How a Change Can Happen
Objective: To study the ways a change is brought about. Learning outcomes - students will be able to: 1. Describe the various ways to bring about a change 2. Illustrate the process of mixing to bring change
