P1.1.2 - The Model of the Atom 2 Flashcards
What did Rutherford discover in 1899?
Ernest Rutherford discovered that some materials emit particles.
What were alpha particles?
The particles that are emitted by some materials
What charge is an alpha particle?
Positive
Who were the two scientists that assisted Rutherford?
Hans Geiger and Ernest Marsden
How did Rutherford explain his results?
He suggested that an atom is made of a tiny, positively charged nucleus with electrons around the outside
What was the Rutherford model?
An atom containing a positive nucleus with randomly encircling negative electrons
What happened when the alpha particles hit a nucleus?
They bounced back
If most of the fired alpha particles went through the atoms, what does this suggest?
The atom is primarily empty
If some of the alpha particle slightly veers off when going through an atom, what does this suggest?
There is a powerful charge located in the atom
If a few alpha particles bounced back from the atom, what does this suggest?
There is something small and heavy in the atom
What did Niels Bohr suggest?
Electrons can only move in fixed orbits
What are electrons shells?
Fixed energy levels/pathways that electrons move in
When was this idea about electron shells introduced?
1913
What is the diameter of an atom?
10 to the power of -10
What are molecules?
A collection of atoms, strongly conjoined and bonded together
