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
Why is Niels Bohr version of the nuclear model in 1919 important
He suggested electrons orbit the nucleus in shells similar to how plants orbit the sun which is important because it meant the atoms wouldnt collapse
Describe the formation of Niels Bohr nuclear model in 1919
Compact nucleus containing a positive charge that is orbited by electrons in shells
Who did further experiments to find the nucleus has protons after Niels Bohr version of the Nuclear model
Ernest Rutherford discovered the atom contained protons in the positively charged nucleus
Who discovered protons in the atom
Ernest Rutherford
Who was the last person to contribute to the history of the atom
James Chadwick
- discovered there were neutral particles in the nucleus (neutrons)
Who discovered neutrons in the atom
James Chadwick
Put these 3 subatomic particles in order of discovery
- Electrons
- Neutrons
- Protons
Electrons
Protons
Neutrons
Put these scientists in chronological order of how the atom was formed to how it is today
John Dalton
Neils Bohr
James Chadwick
Democritus
Ernest Rutherford
JJ Thomson
Democritus 500BC
John Dalton 1800s
JJ Thomson 1897
Ernest Rutherford 1909
Niels Bohr 1913
(Ernest Rutherford again)
James Chadwick
Which scientist contributed to the history of the atom in 500BC
Democritus
Which scientist contributed to the history of the atom in 1800s
John Dalton
Which scientist contributed to the history of the atom in 1897
JJ Thomson
Which scientist contributed to the history of the atom in 1909
Ernest Rutherford
Which scientist contributed to the history of the atom in 1913
Niels Bohr
After Niels Bohr which 2 scientists contributed to the history of the atom
Ernest Rutherford
James Chadwick
