Atomic Structure Flashcards
What is the atom made up of?
The atom is made up of protons, electrons and neutrons
What is most of the space of the atom taken up by?
Most of the space taken up by an atom is the area where the electrons exist
What is at the core of an atom?
The protons and neutrons are in the core of the atom. Referred to as the nucleus
What did the Greeks initially state about the atom?
The greeks (Democritus) stated that if you kept breaking something down, you would get to a size that could no longer be broken. This piece would be the indivisible piece. Thus the atom.
What did John Dalton theorise after the research of the greeks?
Dalton stated that atoms could not be broken down. Atoms formed elements. An element was formed from a collection of the same atom with the same mass and different elements had different masses
What did Jonah Jameson Thomson (J.J Thomson) theorise about atoms after John Dalton’s research?
Thomson determined the mass to charge ratio of an electron. This led him to think there was a more positive part of the atom with a much larger mass. From his theories, he created the plum pudding model.
Describe the appearance of the plum pudding model
In the plum pudding model, the electrons were small and located within the atom in circular arrays, like plums in a pudding of positive charge
Following Thomson’s model, what did Ernest Rutherford do to prompt a change to the model introduced by Thomson?
Ernest Rutherford shot alpha particles at a sheet of gold foil expecting the particles to mostly bounce off. He found that most particles passed through the foil and some bounce back off.
What did Ernest Rutherford conclude from his gold foil experiment?
He concluded that if it was already known that the electron was small and negative, then the atom must have a small positive nucleus with the electrons around them
Following Rutherford’s experiment, who came into the scene and what his theory?
Neil Bohr came into the scene and put forward the idea that the atom consisted of a tiny positive nucleus which was orbited by negatively charged electrons to form an atom.
Following Bohr’s model, who came into the scene and what was his theory?
Schrodinger and Heisenberg introduced a model where the nucleus consisted of the proton middle and the electrons surrounded. However in this model, electrons are said to be in specific regions due to certain probabilities. These probability distributions show the electron has a greater probability of being in the darker shaded areas of the circles
What is the difference between the Bohr model and the Schrodinger model?
The Bohr model states electrons orbit the nucleus in specific positions whereas Schrodinger’s model states electrons do not actually orbit the nucleus and instead there just regions an electron is likely to be
What two reasons are there that an electron does not “orbit” a nucleus in the same way a planet orbits a planet?
Electrons “orbit” due to an electric interaction and not a gravitational interaction. Additionally electrons cannot orbit at any distance and any energy level
In Thompson’s model of the atom, apart from opposite charges, what did he think was the bid difference between the proton and the electron?
Thompson thought another big difference between the proton and the electron was the mass size. The electron has a very small mass and the proton has a much larger mass
What were the three key points for Dalton’s model of the atom?
Dalton said: stuff can be broken into elements, elements are atoms with different masses and lastly compounds are a combination of elements
