Atomic structure quiz Flashcards
Atomic Number
The number of protons in an element
Atomic mass
The average of all elements isotopes
How do you get the atomic mass?
Read right off periodic table
Atomic number
The number of protons and neutrons in combined
How do you get the number of neutrons?
Subtract the atomic number from the mass number
Who is Democritus
Greek philosopher who first came up with the idea of Atoms
Why did Democritus theory not go anywhere?
He had no experimental evidence
Who is John Dalton?
A meteorologist who discovered atoms
What was the first of John Dalton’s points
- All elements are made of invisible particles called atoms
What was the second of John Dalton’s points?
Atoms are identical when they make up the same element
What was the third of John Daltons points?
Atoms of different elements mix or combine in whole number ratios
What did JJ Thompson do
Discovered the electron
How did JJ Thompson discover the electron?
He had a tube of inert gas with a positive and negative charge. The particles were attracted to the positive plate
What was the fourth of John Daltons points?
Chemical reactions occur when atoms separate, join, or rearrange. They never change into another particle however.
What did JJ Thompson prove through his experiment?
The atom was a solid sphere with electrons on either end
