Unit 2 Flashcards
Who created the idea of the atom?
Democritus (400 BC)
Who is considered the father of the atom?
John Dalton (early 1800’s)
What was dalton’s atomic theory?
Each element is composed of small particles called atoms. All atoms of a given element are identical.
Who discovers the electron?
J.J. Thompson (1897)
Who discovers the charge and mass of the electron?
Robert Millikan (1909)
Who discovers the nucleus and is known as the king of noble prizes?
Ernest Rutherford (1911)
Who discovers the proton?
H.G.J Mosely (1913)
Who discovers the neutron?
James Chadwick (1932)
What is the first part of Dalton’s atomic theory?
Each element is composed of small particles called atoms.
What is the second part of Dalton’s atomic theory?
All atoms of a given element are identical. The atoms of different elements are different from one another.
What is the third part of Dalton’s atomic theory?
Atoms of an element are not changed into atoms of another element. Atoms are not created or destroyed (in a chemical reaction).
What gives an element it’s identity?
Protons.
What is the final part of Dalton’s atomic theory?
Compounds are formed when atoms of more than one element are combined. A given compound always has the same relative numbers and kinds of atoms.
What did Dalton’s atomic theory provide an explanation for?
The Law of Constant Composition and The Law Conservation of Mass.
What did Dalton’s atomic theory predict?
The Law of Multiple Proportions
