Math Tutor

Inside The Atom.
An atom has a small central nucleus that contains protons and neutrons. Protons have a positive charge, neutrons have no charge, and together they make up most of the atom’s mass. Surrounding the nucleus are electrons, which have a negative charge and are arranged in shells. These electron shells help explain how atoms behave, bond, and take part in chemical reactions. Understanding atomic structure gives us a strong foundation for learning the rest of Chemistry.

Understanding the difference between elements, compounds, and mixtures is one of the first big steps in Chemistry. An element contains only one type of atom and cannot be broken down chemically into simpler substances. A compound contains two or more elements chemically bonded together in a fixed ratio. A mixture contains two or more substances physically combined, not chemically joined, so they can often be separated by physical methods. Knowing these differences helps us build a strong foundation for everything else in Chemistry.

Lower relative molecular mass → faster diffusion

At the same temperature, all gas particles have the same average kinetic energy…
but lighter particles move faster.

That’s why:

* H₂ diffuses faster than CO₂
* NH₃ spreads faster than Cl₂.

How Particles Spread Without Being Pushed. Diffusion happens because particles are in constant random motion. According to kinetic particle theory, gas and liquid particles move freely and collide with each other, causing them to spread from a region of higher concentration to a region of lower concentration. This continues until the particles are evenly distributed. The process is faster in gases because particles are farther apart and move more quickly than in liquids. Understanding diffusion helps us connect particle motion to everyday observations, from perfume spreading through a room to food colouring dispersing in water.

What heating and cooling curves really mean. Heating and cooling curves are more than just lines on a graph. They show how energy affects particle movement and explains melting, boiling, condensing, and freezing. Through Kinetic Particle Theory, students can see that changes of state happen because particles gain or lose energy and rearrange themselves.

Understanding this isn’t about memorising formulas, but about particles, movement, and collisions.
That’s what examiners are really testing.

Drop a comment:
Which one confused you most — pressure, temperature, or volume?

.KamugishaChristopher

Most students think:

➡️ More heat = higher temperature

But during melting and boiling…
that’s not what happens.

Temperature can stay constant
even when energy is still being added.
Why?
Because the energy is used to break forces between particles,
not to make them move faster.
💡 This is called latent heat
(and it’s where many students lose marks).
If students don’t understand this, they struggle with:

• Heating curves
• Energy changes
• Explaining phase changes properly
🔥 Real understanding = thinking in particles:
Heat energy → breaks attractions → changes state
NOT → increases temperature.
🧠 Quick test:
Which needs more energy — melting or boiling?

IGCSE Chemistry Topic 1 (CIE 0620) using the particle model:

• Why solids keep their shape
• Why liquids flow but don’t compress much
• Why gases are easy to compress
• How particle spacing, motion, and forces explain everything

The key idea students often miss:
States of matter are controlled by the balance between particle motion (kinetic energy) and attractive forces between particles.

Once this clicks, questions become easier:
You stop guessing… and start explaining like the mark scheme expects. ExamPreparation STEMLearning ChemistryTeacher

Time flies by so fast. Make the most of each day while it lasts. #

Learning chemistry, one bond at a time. Stand by you every step of the way, and exploring the fascinating world of chemistry.

2024 Science fair show. Was quite proud of the amount of work these kids put in their projects. Very long hours of hard work including weekends.