Atomic Structure Flashcards
What are elements made up of?
Small invisible particles called atoms
Atoms cannot be…
Created or destroyed
Atoms of different elements have…
Different propersties
When atoms combine they form…
Molecules or compounds
Who proposed the idea that matter is composed of small invisible particles?
Democritus and leucippus
What idea did Aristotle propose?
The matter was composed of the four ‘elements’ air, earth, fire and water, and used these ideas to explain matter and its behaviour.
In 1808 John dalton published his atomic theory. What did he state?
All elements are made up of small atoms called particles
Who discovered the electron?
J j Thompson
What experiment was Thompson carrying out when he discovered the electron?
He was investigating the way conduct electricity goes
In Thompson’s experiment how did he show the electrons had a negative charge?
The electron beam was attached towards the positive plate therefore they must be negatively charged
What did Thompson’s model of the atom look like?
A plum pudding
How did Thompson’s model of the atom look like a Christmas pudding?
Atoms have rings if negative electrons imbedded in a positive sphere like raisins from a pudding
Why did Thompson argue that the atom was neutral?
atoms that contain negatively charged electrons must also contain positively charged material.
What did Rutherford discover about the atom?
Rutherford overturned Thomson’s model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus.
Where is virtually all of an atoms mass contained?
Virtually all the mass of the atom resides in the nucleus
In what way was Rutherford model of an atom similar to planets revolving around the sun?
Rutherford believed that the electrons within an atom moved around the nucleus in orbits
What part of the atom did James Chadwick discover in 1932?
The neutron
How does the mass of a neutron compare with the mass of a proton?
Protons and neutrons have approximately the same mass, but they are both much more massive than electrons
Atom is composed of small, dense, … charged nucleus at the center composed of … and … (most of the mass) with … charged electrons in … orbiting the …
Positively Protons And neutrons Negatively Shells Nucleus
What is a protons relative mass?
1
What is a protons relative charge?
+1
What is protons position?
Nucleus
What are neutrons relative mass?
1
What is neutrons relative charge?
0
What is protons position?
Nucleus
What is electrons relative mass?
1/1840