EXAMS 2026 TESTED QUESTIONS AND
COMPLETE SOLUTIONS GRADED A+
⩥ Daltons atomic theory. Answer: -all matter is made up on invisible
particles
-all atoms of an element are identical
-atoms of different elements are different
-atoms cannot be created or destroyed
⩥ JJ Thompson. Answer: used the cathode ray tube to propose atoms
contained electrons
⩥ Rutherford. Answer: gold foil experiment determined the nucleus is
made up of protons
⩥ Chadwick. Answer: proposed nucleus also contains neutrons
⩥ Bohr. Answer: showed electrons exist in fixed levels using the light
experiment
⩥ isotope. Answer: an atom with the same number of protons but
different number of neutrons
, ⩥ radioactive. Answer: when an isotope is unstable and causes the
nucleus to decay and emit radioactive gamma rays
⩥ quantum. Answer: one burst or packet of energy
⩥ photon. Answer: a unit of electromagnetic energy
⩥ red light. Answer: longest wavelength, lowest frequency, lowest
energy visible light
⩥ purple light. Answer: shortest wavelength, highest frequency, and
higher energy
⩥ Schrodinger defines an orbital as. Answer: a region around the
nucleus where an electron has a high probability of being found
⩥ Heisenberg's uncertainty principle. Answer: it is impossible to know
the exact position and velocity of an electron at the same time
⩥ quantum numbers. Answer: each electron in an atom can be assigned
a set of unique numbers that describe where the electron is likely to exist