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Mr Chen's anecdotes.


Atomic structure is usually the first chapter taught in Chemistry, for both O and A level. It is generally a simple topic that most students would excel in. The concept taught is simple and minimum memory work is required.

Here are 3 things to take note of when you're learning atomic structure in Chemistry.

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Electronic Configuration & Diagrams

First and foremost, you will be taught about the existence of sub-atomic particles. Namely, protons, electrons and neutrons. You will learn to identify the number of each particle via the periodic table.

The difficulty subsequently increases when a dot and cross diagram of an atom is presented to you. You are to learn to identify the number of each sub-atomic particles based on the diagram drawn. The converse is also true. You will be given the number of each particle and asked to draw the dot and cross diagram.

A very simplified model of atoms

Furthermore, you will also learn to write the electronic configuration of an atom.

All this information will be put together and related to the periodic table in terms of Group Number and Period Number.

I hope the above doesn't sound too intimidating. It really isn't hard.


Isotopes, many would argue, is the only interesting section of this chapter.

Atoms with the same number of protons but different numbers of neutrons are called isotopes.

For most Secondary 3 Weighted Assessments, the definition of isotopes would be asked. Students are to understand that number of neutrons is not unique to an element. The same element could exist as different atoms with a different number of neutrons.

Example of a commonly tested question

Most questions regarding isotopes would be in the form of a table. It is commonly tested as the first question of section B. A table with information about the unknown atoms would be presented. The student would then be asked to identify the isotopes and ions etc.

Most students tend to score full credit for such questions lest careless mistakes.

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Disconnect Between O level & A level Chemistry

The atomic structure you learn in O level are half truths.

O level Chemistry content are half truths

In the gif I pinned above, it is considered too simple for A level. Atomic structure at higher levels can get very complicated mainly due to the existence of sub-shells. It could stretch as far as orbital levels for undergraduate studies which are too abstract even for the likes of me.

However, this simplified model that you learned in O levels are still relevant because it forms the fundamental understanding regarding how elements can achieve stability.

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Nothing To Worry About

Chemistry and Math tutors are highly sought after for their ability to break down complicated problems into bite-size information. We, at VANTAGE TUTOR, have struggled and walked through a similar path to students when they were students themselves. We understand where you fall short and in hindsight, we also realized how we could have done better for our O level Chemistry.

We will achieve basic mastery before applying to problem-based questions. Furthermore, our tutors have a track record in helping students improve in physics for N level, O level, A level, and even IP!

So, don't worry about the confusion and dissonance you would feel when you get to H2 Chemistry.

You can always call me.

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