History of Atom Flashcards
What is matter?
Matter is anything that takes up space and has mass.
Law of conservation of matter
Matter cannot be created or destroyed but can be changed from one form to the another.
What were the contributions of Greeks towards the discovery of atoms?
Greeks proposed the four elements earth, fire, wind and water.
Idea that matter was made up of small particles which are indivisible.
What is diffusion?
Movement of particles from region of higher concentration to lower concentration that does not require energy.
Describe the laboratory experiment to demonstrate the diffusion of gases?
Explain how this is the evidence for the particulate nature of matter?
What is the particulate nature of matter?
What is atomic theory?
Who discovered cathode rays?
William Crookes
Describe how Crookes discovered cathode rays?
What is cathode rays?
Cathode rays are streams of negatively charged particles called electrons.
What are the properties of cathode rays?
- Travelled in straight lines
- caused glass to fluoresce
- Has enough energy to move a paddle wheel.
Who discovered electron?
J J Thomson
Describe how he discovered electron?
Describe ‘plum pudding model’ proposed by Thomson?
Who gave the name electron to negatively charged particles?
George Stoney
Who measured the size of charge on the electron?
Robert Milikan
What were the three observations made by Rutherford’s team when they bombarded gold foil with alpha particles?
Describe how Milikan did the experiment?
Who discovered nucleus?
Ernst Rutherford
Describe how Rutherford discovered nucleus.
Who discovered proton?
Ernest Rutherford
Who discovered neutron?
James Chadwick
Describe how Chadwick found neutron?
Chadwick bombarded a sample of beryllium with alpha particles.
Some type of radiation consisting of particle with no charge came out of Berylllium.
