CHEMISTRY Flashcards
Democritus
Democritus came up with the first ideas of an atom. His theory was not used because he could not explain what held atoms together.
What is special about an element?
It cannot be broken down. Simplest form. Each element is unique because of the amount of protons
4 parts of Dalton’s Atomic Theory of Matter
-All matter is made of atoms.
-All atoms of the same elements have the same properties.
-Compounds are formed when atoms of two different elements join together
-A chemical reaction is a rearrangement of atoms.
What is a anion?
Molecules with a negative charge.
What is a cation?
Molecules with positive charges.
What did Thomson find?
Thomas discovered opposites attract, and the exact charge of electrons. (cathlode ray tube)
How did Thomson discover his findings?
A cathode ray tube.
What was Thomson’s model of an atom called?
“Plum pudding model”
Why was Thomson’s model important if it was wrong?
Even though the model was wrong, it was a large development of Atom theory history.
What did Millikan do?
Millikan conducted an oil drop experiment.
Why was the oil drop experiment important?
Millikan discovered the mass of an electron.
What was Rutherford’s experiment?
He shot alpha particles at gold foil.
What did Rutherford discover in his experiment?
He saw that some particles bounces back at him. He discovered the nucleus of an atom.
How does an ion form?
An ion forms when an atom gains or loses electrons.
What is an Isotope?
Atoms that have the same number of protons and electrons but different numbers of neutrons.
