What are the different types of JC Chemistry tuition classes available at your centre?

We have 3 modes of learning for students to choose from: weekly physical classes at Bishan; weekly online lessons via Zoom; and on-demand video lessons.

Are you the only Chemistry tutor conducting the classes or do you engage other tutors to do that?

Please be rest assured that I conduct all my classes personally and I do not engage other tutors to teach at my centre.

How well do your students perform after attending your H2 Chemistry tuition classes?

Most of my students showed improvements by at least 3 grades and more than 80% have attained distinction for A Levels. The earlier the students join my classes, the more confident I am in improving their grades.

What is your class size at Bishan?

Usually the class size is around 10 to 12 students. Max class size is 16 pax.

Is there makeup lesson if I miss a class?

Yes makeup lesson is available in the same week subject to availability. If makeup class is not possible, the student can view the recorded video lessons at Google Classroom.

Do you have trial lesson available? How much is it?

Yes we do. Fees for trial lesson are for Bishan class and for Zoom online class.

Does your centre offer O Level chemistry tuition? Do you teach IB / IP chemistry tuition? How about H1 Chemistry?

Chemistry Guru specialises in H2 Chemistry for JC1 and JC2 or IP Year 5 and IP Year 6 students only. Find out all the information about A Level H2 Chemistry and the detailed comparison between H1 and H2 Chemistry. We do not conduct lessons for H1 Chemistry, O Level Chemistry, IB Chemistry or IP Chemistry at IP Year 3 and IP Year 4.

Compare Melting Point of Ionic Compounds

In this video lesson created by Chemistry Guru, Singapore's leading JC Chemistry tuition centre let us compare the melting point of ionic compounds.

The strength of ionic bonds in ionic compounds is related to lattice energy via the following expression:

230417 lattice energy

where
q⁺ is the charge of cation
q^- is the charge of anion
r₊ is the radius of cation
r_- is the radius of anion

Notice the denominator term (r₊ + r_-) is simply the distance between the cation and anion.

So in general, the greater the charges of the ions and the shorter the distance between the ions, the magnitude of lattice energy will be greater.

This means more energy is required to overcome the stronger ionic bonds and that ionic compound will have a higher melting point.

In most questions, we only need to consider one of the 4 terms in the lattice energy expression.

Let's compare the melting points between Na₂O and MgO as an illustration.

The difference will be in the cations Na⁺ and Mg²⁺.

Mg²⁺ has a higher charge and smaller radius than Na⁺, but the 2x increase in charge is more significant than the small difference in radius so we can just focus on the q⁺ term.

The difference in radius is small because both Na⁺ and Mg²⁺ are isoelectronic with 10 electrons, so they will both have 2 filled principal quantum shells with roughly the same size.

230417 Na2O vs MgO