Topic 1 - Atomic structure and the periodic table (2) Flashcards
HISTORY OF THE ATOM:
What was the first model of the atom?
Who created it and when?
at the start of the 19th century, John Dalton described atoms as solid spheres and said that different spheres made up the different elements
HISTORY OF THE ATOM:
What did John Dalton say about the atom?
he described the atoms as solid spheres and said that different spheres made up the different elements
HISTORY OF THE ATOM:
What did JJ Thompson conclude from his experiments?
When did this happen?
What did he call his new model?
- atoms weren’t solis spheres, he concluded from his measurements of charge and mass showed that an atom must contain even smaller, negatively charge particles - electrons.
- 1897
- the became the ‘plum pudding model’
HISTORY OF THE ATOM:
Who discvered electrons and when?
J J Thompson
1897
HISTORY OF THE ATOM:
Who proved the plum pudding model to be wrong?
Ernest Rutherford
HISTORY OF THE ATOM:
Who conducted the alpha particle scattering experiments and when?
1909
Ernest Rutherford and his student Ernest Marsden
HISTORY OF THE ATOM:
What did they do in the alpha particle scattering experiment?
fired positively charged alpha particles at a thin sheet of gold
HISTORY OF THE ATOM:
Using the plum pudding model, what was expected to happed during the alpha particle scattering experiment and why?
- they were expecting the particles to pass stright through the sheet or be slightly deflected at most
- because the positive charge of each atom was thought to be spread out through the ball of positive charge
HISTORY OF THE ATOM:
What happened during the alpha particle scattering experiment which meant the plum pudding model could not be right?
whilst most of the particles did go straight through the gold sheet, some were deflected more than expected, and a small number were deflected backwards
HISTORY OF THE ATOM:
What model of the atom did Rutherford come up with after the alpha particle experiment?
the nuclear model
HISTORY OF THE ATOM:
What issue was foung with the idea that a ‘cloud’ of electrons surrounded the nucleus as Rutherford described?
the electrons would be attracted to the nucleus which would cause the atom to collapse
HISTORY OF THE ATOM:
How was Niel’s Bohr’s nuclear model different to Rutherford’s
- he suggested that the electrons were contained in shells
- he proposed that electrons orbit the nucleus in fixed shells and aren’t anywhere inbetween
- each shell is a fixed distance from the nucleus
HISTORY OF THE ATOM:
In what order were the subatomic particles discovered?
electron
proton
neutron
HISTORY OF THE ATOM:
Who discovered the proton?
Ernest Rutherford
(he showed that the nucleus cn be divided into smaller particles, which have the same charge as a hydrogen nucleus)
HISTORY OF THE ATOM:
When was the neutron discovered and who by?
1932 by James Chadwick
HISTORY OF THE ATOM:
What is the name of the model of the atom that we use today?
the nuclear model
ELECTRONIC STRUCTURE:
What can shells also be called?
energy levels
ELECTRONIC STRUCTURE:
What number of electrons can fit on each shell?
1st - 2
2nd - 8
3rd - 8
ELECTRONIC STRUCTURE:
What will an atom do if it does not have a full ouer shell?
react to fill it
ELECTRONIC STRUCTURE:
Atoms are unreactive when …
they have a full outer shell
ELECTRONIC STRUCTURE:
Nitrogen’s atomic number is 7, what is it’s electronic structure?
2, 5
ELECTRONIC STRUCTURE
Magnesium has an atomic number of 12, what is it’s electronic structure?
2, 8, 2
PERIODIC TABLE DEVELOPMENT:
What two ways COULD elements have been categorized by in the early 1800s?
1) physical and chemical properties
2) their atomic weight
(as they didn’t know about any of the subatiomic particles)
PERIODIC TABLE DEVELOPMENT:
How were elements arranged in the early 1800s?
What were the issues with this?
By their atomic weight
not all elements had been discovered
so early periodic tables were incomplete and some elements were placed in the wrong group as their properties were not taken into account
