Science Made Easy: ‘Practice makes you perfect’, says the educator

Just like Math, Science is a scoring subject and teachers will tell you that if you have understood the concepts clearly, there is no reason why the student would lose even a single mark in their test or exam. And this is where the problem lies. For most students, the concepts in Science are not clear. Therefore, they find the subject tough to crack, especially when they come to higher classes and there are three different books – Physics, Chemistry, and Biology. In most cases, each book will have at least 10 chapters.

This is the first stumbling block – the huge syllabus that is staring at them. Teachers say that is a major reason why some students give up trying. ‘It is impossible for me to study so many chapters’ is a commonly heard statement from such students. However, this is not true.

“In class X students are taught balancing the equations. To make it easy for students to remember the elements and their symbols, we gave them a simple mnemonic. There are several such mnemonics that are taught from time to time. This makes it easy for them to remember the names of the elements”

–Suman Chaudhary, Chemistry teacher at Apeejay School, Sector 15 in Faridabad

Suman Chaudhary, a Chemistry teacher at Apeejay School, Sector 15 in Faridabad, who teaches classes X to XII, said that just like Math, Science needs practice as well. “Students need to remember what has to be taught in earlier classes too. When students come to class X, we revise what they have learnt in class IX – learn the symbols of elements, how combine elements to form compounds, how to write valency and electronic configuration,” Chaudhary said

In class X students are taught balancing the equations. “To make it easy for students to remember the elements and their symbols, we gave them a simple mnemonic. Take an example, Kedar Nath Ca Mali Aloo Zara Fike Se Pakata Hai Cyuki Har taraf Alag Auloo Padta Hai,” Chaudhary said.

Here: Kedar: K – Potassium, Nath: Na – Sodium, Ca: Ca – Calcium, Mali: Mg – Magnesium, Alu: Al – Aluminum, Zara: Zn – Zinc, Fike: Fe – Iron, Se: Sn – Tin, Ptaka: Pb – Lead, Hain: H – Hydrogen, Cyuki: Cu – Copper, Har: Hg – Mercury, Alag: Au – Silver, Auloo: Au – Gold, Pdta: Pt – Platinum

“Similarly, there are other mnemonics that are taught from time to time. This makes it easy for students to remember the names of the elements. For now, we teacher first 20 elements only. We teach scientific names of the elements too so that the students don’t get confused. All the 118 elements are no longer part of the syllabus due to the deletion in the course in class X,” Chaudhary said.

What are the steps involved in balancing chemical equations?

1. Know the symbol of the element. For example, Na is for Sodium; H is for Hydrogen.

2. Then comes atomic numbers. The students are taught mnemonics.

3. The student should know the valency; for an atom it is equal to the number of electrons in the outer shell if that number is four or less. If it is more than four, it is subtracted from 8.

4. Knowledge of electronic configuration is important.

For example, electronic configuration of Sodium Chloride: Atomic number of Sodium (Na) atoms is 11. Electronic configuration is: Na = 2, 8, 1. It contains 1 valence electron. In order to achieve the nearest noble gas configuration, it loses one electron to form Sodium ion. Na+: 2, 8. Atomic number of Chlorine (Cl) atoms is 17. Electronic configuration is: Cl = 2, 8, 7. It contains 7 valence electrons. In order to achieve the nearest noble gas configuration, it gains one electron to form Chloride ion. Cl-=2, 8, 8. And it becomes Nacl.

“To teach the students what a balanced equation is, we tell them that it is like a seesaw. If the weight at each end is unequal, the seesaw will not be straight. For this, the weight at either end has to be the same. An equation that has an equal number of atoms of each element on both sides of the equation is called a balanced chemical equation,” Chaudhary said and added that the rule that applies is that mass can neither be created nor destroyed.

How to balance an equation?

For example, P4O10 + H2O → H3PO4, There are four atoms of phosphorus on the left-hand side, but only one on the right-hand side.

We put 4 on the molecule that has phosphorus on the right-hand side to balance them out. P4O10 + H2O → 4 H3PO4.

We check hydrogen. There are two molecules of hydrogen on the left-hand side and 12 on the right-hand side.

To balance those out, we have to put a six in front of H2O on the left. P4O10 + 6 H2O → 4 H3PO4.

We check oxygen. On the left, we have 10 atoms of oxygen from P4O10 and six from H2O for a total of 16. On the right, we have 16 as well.

So the final balanced equation is: P4O10 + 6 H2O → 4 H3PO4.

“Students must also have knowledge of which elements can exist alone. Metals exist alone. Na exists alone; Calcium exists alone. In the case of non-metals like chlorine, it is present in the form of Cl2. Oxygen is O2. These are some of these rules that the students need to learn,” Chaudhary said in conclusion.