Topic 1-Atomic Structure and the Periodic Table Flashcards
What methods are there to separate mixtures?
Filtration Crystallisation Simple distillation Fractional distillation Chromatography
What was the plum pudding model?
The concept that an atom was a ball of positive charge with negative electrons embedded in it
What was Rutherford’s alpha particle scattering experiment?
A beam of alpha particles was aimed at very thin gold foil and their passage through was detected
Some of the alpha particles emerged from the foil at different angles and some even came straight back
The positively charged alpha particles were being repelled and deflected by a small concentration of positive charge in the atom (nucleus)
What was concluded after the particle scattering experiment?
It was concluded that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged
Who suggested that electrons orbited the nucleus at specific distances?
Niels Bohr
How did James Chadwick contribute to the atom model?
He provided the evidence to show the existence of neutrons within the nucleus
What is the radius an atom?
0.1nm
1x10^-8cm
What is the radius of a nucleus?
1x10^-14
Less that 1/10,000 of that of the atom
What are isotopes?
They are atoms of the same element with different numbers of neutrons
How do you calculate relative atomic mass?
((isotope 1 mass x abundance) + (isotope 2 mass x abundance)) ÷ 100
Describe and explain chromatography
Draw line with pencil on filter paper
Add spot of ink then place paper in solvent (not touching to avoid dissolution)
The solvent will slowly rise, separating the spot into few spots.
In chromatography, why must you use a pencil to draw the line and not a pen?
Pen ink is soluble and will dissolve in the solvent
In chromatography, what is the end result called?
It is called a chromatogram
Why must you place a lid on top of the solvent in chromatography
This is to stop the solvent from evaporating
Describe and explain simple distilation
The solution is heated and the part of the solution that has the lowest boiling point evaporates first
The vapour is cooled, condenses and is collected
The rest of the solution is left behind in the flask
What is the problem with simple distilation?
You can only use it to separate things with very different boiling points