Atoms + radiation Flashcards
(59 cards)
What is the nucleus?
The centre of the atom, containing protons and neutrons.
What are electrons?
Negatively charged particles that orbit the nucleus at fixed distances.
What is the radius of atoms?
1 x 10^-10 metres
What is the mass and charge of protons?
Mass=1
Charge= +1
What is the mass and charge of neutrons?
Mass=1
Charge=0
What is the mass are charge or electrons?
Mass=1/1800
Charge=-1
What is the mass number?
Top number, protons + neutrons.
What is the atomic number?
Bottom number, protons and electrons.
What are isotopes?
An element with the same number of protons but different numbers of neutrons.
Define ionisation
The process of an atom becoming a charged particle (make an ion).
What is emission?
When an electron emits energy as it moves down an energy level.
When do atoms become charged?
When they lose or gain electrons.
When is a positive ion formed?
When an atom loses one or more electrons.
When is a negative ion formed?
When an atom gains one or more electrons.
When do electrons move up an outer shell?
When they gain energy by absorbing electromagnetic radiation.
Who created the Plum Pudding model and when?
JJ Thompson in 1897.
What did JJ Thompson discover?
The electron.
What does the Plum Pudding model look like?
A cloud of positive charge with negative electrons embedded in it.
Who created the Nuclear Model of the atom and when?
Ernest Rutherford in 1911.
What did Ernest Rutherford discover?
A small positive nucleus in the atom.
How did Rutherford discover the nucleus?
Discovered it in his alpha scattering experiment.
What does the Nuclear model of the atom look like?
Ball with electrons orbiting the nucleus but not at set distances.
What was step one of the alpha scattering experiment?
1 = Alpha particles (small, positively charged particles) fired at thin gold foil.
What was step two of the alpha scattering experiment?
2 = The scientists were expecting the alpha particles to go straight through the gold.
