Physical Science
Matter and chemistry
Know atomic structure (protons, neutrons, electrons), isotopes, and ions, and how periodic position predicts reactivity: metals lose electrons, nonmetals gain or share, noble gases are stable. Balance simple equations using conservation of mass - atoms are rearranged, never created or destroyed. Separate physical changes (phase, shape) from chemical changes (new substances), and remember that density is an intensive property that does not change with sample size. One mole equals 6.02 × 10^23 particles; molar mass converts grams to moles.
Physics
Separate concepts the exam likes to blur: mass (amount of matter) versus weight (gravitational force, mg); speed (scalar) versus velocity (vector with direction); energy (capacity to do work, in joules) versus force (a push or pull, in newtons). Newton's laws explain inertia, F = ma, and action–reaction pairs acting on different objects. Energy is conserved but transforms and degrades toward heat. For waves, frequency × wavelength = speed; for circuits, Ohm's law (V = IR) and series versus parallel behavior are standard.
Worked example
A 2 kg cart accelerates at 3 m/s². Net force = ma = 2 × 3 = 6 N. If friction is 1 N opposing motion, the applied force must be 6 + 1 = 7 N. A frequent trap is adding friction in the wrong direction.
Traps
Heat versus temperature, mass versus weight, and the claim that energy is "used up" (it is transformed, not destroyed).