Atomic Structure Flashcards
Describe what happens when an electron drops to a lower energy level in an atom.
Releases a photon of electromagnetic radiation.
Which scientific discovery resulted in the solid atom theory being adapted into the “plum pudding” model of the atom?
The electron (1987).
Rutherford carried out an experiment to show alpha particles either passing through gold leaf, being scattered by it. Summarise the conclusions he made from this experiment.
Passing through suggests atoms are mostly empty space.
Deflected suggests nucleus has same charge as the alpha particle (positive).
Reflected suggests nucleus is where most of the mass of the atom is.
What contribution did Niels Bohr make to the arrangement of electrons in the atomic model?
He realised that electrons orbit nucleus in clearly defined energy levels, at different distances from the nucleus.
What is radioactive decay?
When atoms give out radiation to make their nuclei more stable.
Which part of an atom is involved with radioactive decay?
Nucleus only.
Explain the meaning of the term activity, as applied radioactive materials and state the units of activity.
The rate at which a source of unstable nuclei decays - Bq.
What is ‘count rate’?
The number of radioactive decays recorded in a given time.
