ATOMIC STRUCTURE AND PERIODIC TABLE Flashcards
What is the atomic number?
The number of protons/electrons
What is the mass number?
The total number of protons and neutrons
What are isotopes?
Elements that have the same number of protons but different number of nuetrons
How do you work out the relative atomic mass for an element with isotopes?
sum of each (isotope abundance x isotope mass number) / sum of abundances of all the isotopes
What are compounds?
Substances formed from two or more elements
What is filtration?
Separating insoluble solids from liquids
What is evapouration?
Pour solution (containing soluble solid) on an evaporating basin
Slowly heat
What is crystallisation?
Pour solution (containing soluble solid) into an evaporating dish
Slowly heat
Remove dish from heat and cool till crystals form
Filter crystals from solution then dry
What is simple distillation?
Used for separating a liquid from a solution
How does simple distillation work?
Solution is heated
Whatever has the lowest boiling point will evaporate first
Vapour is then cooled and condenses and collected
The rest is left behind in the flask
What is fractional distillation?
Used to separate a mixture of liquids
How does fractional distillation work?
A fractional column is placed on top of the flask
Lowest boiling point is collected first when at the top of the flask it reaches that temp
Others may start to evaporate but it is cooler at the top so they will condense down again
What is the history of the atom?
Plum pudding model (John Dalton)
Nuclear model (Rutherford)
Bohr’s nuclear model
What does the plum pudding model show?
A ball of positive charge with electrons stuck in it
What does the nuclear model show?
Positively charged nucleus with a cloud of negative electrons