P1.1.2 - Model Of The Atom 2 Flashcards
What did Ernest Rutherford discover in 1899?
That some materials emitted particles called alpha particles
What charge did alpha particles have?
Positive
What did Rutherford then decide to do?
Fire alpha particles at piece of gold foil
What did Rutherford suggest in order to explain his results?
He said that an atom is made of a tiny, positively charged nucleus which contains almost all the mass.
The nucleus is surrounded by negatively charged electrons
What did scientists later discover?
The nucleus was made of protons and neutrons
What was the problem with Thomson’s model?
You would expect the electron to spiral until they hit the nucleus.
What did Niels Bohr suggest in 1913?
Electrons can only move in fixed orbits called electron shells around the nucleus
What is the diameter of an atom?
1x10^-10m
1 times 10 to the power of minus 10 metres
What are molecules?
Collections of atoms
