P1 - 1.7 The History Of The Atom Flashcards
Atomic Structure & The Periodic Table
Name the 6 people involved in the History of the Atom
500 BC Democritus
1800s John Dalton
1897 JJ Thomson
1909 Ernest Rutherford
1913 Niels Bohr
(Ernest Rutherford again)
James Chadwick
Who started the History of the atom in 500 BC
Democritus 500BC
- created the “Atomic Theory” which meant he believed everything was made up of particles that cant be broken down any further
- atoms are separated from each other via empty space
What did Democritus (500BC) believe the atom was
(History of the Atom)
He created the “Atomic Theory” and he believed that everything was made up of particles that cant be broken down any further and atoms are separated from each other via empty space
Who was the second person to contribute to the History of the atom in the 1800s
John Dalton was the second person to contribute to the history of the atom and he described atoms as “solid spheres” and he believed different types of spheres made up the different elements
What year did John Dalton contribute to the history of the atom
1800s
Who was the third person to contribute to the history of the atom in 1897
JJ Thomson
- he created the plum pudding model where it is a ball of positive charge with electrons floating in it
- carried out a number of experiments to prove John Daltons idea of the atom wrong and they must contain a negatively charged particle (electrons)
What year did JJ Thomson contribute to the history of the atom
1897
Who created the plum pudding model
JJ Thomson
Describe the formation of JJ Thomsons Plum Pudding Model
A ball of positive charge with electrons floating in it
Who was the fourth person to contribute to the history of the atom in 1909
Ernest Rutherford (and his students)
- used alpha particles and a thin strip of gold to test JJ Thomsons plum pudding model and proved it wrong as the alpha particles reflected to the side and some deflected back in the direction they came
- created the nuclear model that was a compact nucleus containing a positive charge surrounded by a negative charge in form of a cloud
- this would prove however the atom would automatically collapse as there is no structure to the negative cloud which we know it doesnt
Who was the fourth person to contribute to the history of the atom in 1909
Ernest Rutherford (and his students)
- used alpha particles and a thin strip of gold to test JJ Thomsons plum pudding model and proved it wrong as the alpha particles reflected to the side and some deflected back in the direction they came
- created the nuclear model that was a compact nucleus containing a positive charge surrounded by a negative charge in form of a cloud
- this would prove however the atom would automatically collapse as there is no structure to the negative cloud which we know it doesnt
What year did Ernest Rutherford contribute to the history of the atom
1909
Describe the formation of the nuclear model created by Ernest Rutherford
Compact nucleus containing all positive charge surrounded by a negative charge in the form of a cloud which
How do we know Ernest Rutherford’s nuclear model cant be correct in 1909
He stated that it had a negative charge in the form of a cloud surrounding the compact nucleus which should cause the atom to collapse as there is no structure to the negative cloud which we know wont work because atoms dont collapse
Who was the fifth person to contribute to the history of the atom in 1919
Niels Bohr
- suggested electrons orbit the nucleus in shells similar to how plants orbit the sun
