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SingaporeCombined Science

Chemistry: Atoms, Bonding and the Mole

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is an atom made of, and how does its structure explain the periodic table?

Describe the structure of the atom, define proton number and nucleon number and isotopes, and relate electronic configuration to the position of an element in the periodic table
A focused answer to the O-Level Combined Science outcome on atomic structure. Protons, neutrons and electrons, proton and nucleon number, isotopes, electron shells, and links to the periodic table.
8 min answer →

How do atoms join together, and how does the type of bond explain a substance's properties?

Describe ionic and covalent bonding in terms of electron transfer and sharing, and relate bonding to the properties of ionic compounds and simple molecules
A focused answer to the O-Level Combined Science outcome on bonding. Ionic bonding by electron transfer, covalent bonding by sharing, and how the type of bonding explains melting points and conductivity.
8 min answer →

How does the particle model explain the states of matter and how they change?

Describe the arrangement and motion of particles in solids, liquids and gases, and explain changes of state, diffusion and the kinetic particle theory
A focused answer to the O-Level Combined Science outcome on the particulate nature of matter. The kinetic particle theory, the three states and their arrangement, changes of state, and diffusion.
8 min answer →

How do we count atoms by weighing, and how do we use the mole to work out reacting masses?

Define relative atomic and molecular mass and the mole, and use moles to calculate reacting masses and amounts from balanced equations
A focused answer to the O-Level Combined Science outcome on the mole. Relative atomic and molecular mass, the mole and Avogadro's number, the moles equation, and simple reacting-mass calculations.
9 min answer →