The nuclear atom Flashcards
Describe Thomson’s plum pudding model
Electrons are embedded in a positively charged sphere , and there’s an equal number of protons and electrons
What particles were used in Rutherford’s gold foil experiments?
Alpha particles
What proved that the atom is mostly empty space?
Most alpha particles travelled straight through the gold foil undeflected
Why are some alpha particles deflected by small angles?
The positive alpha particles are repelled by the positive nucleus
Why are a small number of alpha particles deflected straight back towards the source?
The nucleus is very small.
- Carries most of the atom’s mass.
- The charge is concentrated at the nucleus
What else was proved by most alpha particles travelling straight through undeflected?
The nucleus is very small and most of the atom’s mass is concentrated at the centre
What is mass / nucleon number (A)?
The sum of the protons and neutrons in the nucleus
What is proton number (z) ?
The number of protons
What is a nuclide?
A different combination of nucleus that forms a type of atom
What are isotopes?
Elements with the same number of protons but a different number of neutrons
What is it called when isotopes are used to find the age of dead organisms?
Carbon dating
What process takes place in nuclear reactors to produce nuclear energy?
Nuclear fission
What is nuclear fission?
When a nucleus splits up into two smaller nuclei
What process releases energy inside the sun?
Nuclear fusion
How does nuclear fusion happen in the sun?
Two energetic hydrogen atoms collide and fuse to form a helium atom
