anatomy of an atom

Question 1

Which scientist greatly advanced x-ray crystallography to determine the structure if biomolecules?

Answer 1

Dorothy Hodgkin.

Question 2

What does wavelength determine?

Answer 2

whether high energy particles will travel through a sample.

lambda = h/mv

Question 3

How did JJ Thompson work out the mass of an e-?

Answer 3

using CRT
generated e- & passed them through a field
measured diffraction when they hit a scintillating surface.

Question 4

How did Millikan work out the charge of an e-?

Answer 4

• passed charged oil droplets through an electric field
• charged water droplets falling, using electric field stopped them falling, could work out the charge from the gravity-electricity imbalance.

Question 5

How did Rutherford’s experiment to determine structure of the atom conclude modern day model?

Answer 5

• used alpha particles (2 protons & 2 neutrons from RaBr2), fired them at gold, measuring angles, majority of particles went straight & through zinc sulphide screen, some were deflected & went through the screen, very small amount went straight backwards.
• because such small number of the positive alpha particles went backwards, the nucleus must be very small relative to the area/size/width of the atom.

Question 6

Bohr’s theory of atom

Answer 6

• electrons must be moving unless they will crash into the nucleus, therefore must be given energy
• nucleus & e- are electrostatically attracted
• momentum is constant because energy is constant
• but why are energy levels quantized (discrete)? We explain this by describing particles using equations as wave-like. (Schrodinger’s equation).