General topics for preliminary examination - Science - Chemistry special #27
In competitive examinations, chemistry is similar to physics. UPSC may ask 1-2 questions or may leave out completely. In TNPSC every year some questions are asked. It is essential to utilise our time and efforts with a clear understanding of how much to invest in a topic from which only a few questions will come. In competitive examinations, an essential skill for all to have is the ability to manage their time to ensure optimal productivity. “I am an average student. Can I get IAS?” If a student asks me this, my only answer will be that “if you work hard, you surely can.” However if the same student asks me, “I keep wasting my time in useless pursuits, can I get IAS,” my sure answer will be that “until you learn to stop wasting time, you cannot get IAS.” This your success and failure will depend on your time management. It is to make this easier for you, I am listing out the important topics.
In chemistry, first learn about matter and its forms such as solid, liquid, gas, mixtures, etc., the ways to separate compounds, such as filteration, crystallisation, distillation, etc., atomic structure and its parts, Thomson model, Rutherford model, Bohr model, parts of an atom, etc. Some one line definitions from this topic are listed below:
Atomic number ( Z ) - number of protons in an atom (if it is a neutral atom, it will be the same as the number of electrons)
Mass number (A) - Sum of the number of protons and neutrons in an atom
Atomic mass - The sum of all electrons, protons, neutrons, etc., in an atom.
Isotopes - elements with same atomic number but different mass number
Isobars - elements with same mass number but different atomic number
It is essential to learn about major concepts like these. Similarly, Bohr-burry scheme, Aufbau’s law, Hund rule, Pauli’s principle, etc., should be studied.
Radioactivity and its applications, chemical bonding, main chemical reactions (salient points only), electro chemistry, acids, salts, other chemicals, etc., and importantly their applications in our everyday life need to be studied. The next important topic we shall see is the Periodic Table - its different models, main features, etc., are to be learned. Similarly questions have been asked about the major metals and ores as well.
Which of the following is correct
Cinnabar is an ore of mercury.
Cassiterite is an ore of lead.
Both are correct ( answer )
Both are wrong
Main metals and their compounds - with their names and applications - can be made into a table and studied. Learn the names of major alloys. Carbon, hydrogen, phosphorous, sulphur, and other main elements can be studied with notes. Chemicals used in food items are very important for competitive examinations. Similarly chemicals we use in everyday life, chemicals that impact the environment, etc., can be studied.
Items we use - needless chemicals that are contained in them
Lip stick - lead
Cool drinks - brominated vegetable oil
Chinese fast foods - Mono Sodium Glutamate
Which of these are correctly matched?
2 and 3
1 and 3
1,2,3 ( answer )
Therefore in chemistry, unlike our school and college days, we don’t have to memorise every equation or go in too deep. Basic knowledge and knowledge about everyday items are enough. We shall meet in next topic.
- We shall win!