GCSE Paper 1 Flashcards
What is the radius of an atom?
1 x 10 - 10m
Whats the radius of a nucleus?
1 x 10-14m
Def ionic bonding
When a metal and a not metal lose and gain electrons which causes them to be strongly attracted to each other
Def covalent bonding
When non-metals share electrons to become bonded together
What is the formula for ammonia?
NH3
How can you separate an insoluable solid from a liquid?
Filtration
How can you separate a soliable solid from a liquid? (2)
Evaporation
Crystallisation
When would you have to use crystallisation instead of evaporation
If the salt doesnt decompose when heated
What is simple distillation used for?
To seperate out solutions
How do you do simple distillation?
The solution is heated (lower boiling point solution evaporates first)
The vapour is then cooled and condensed down to a liquid
The rest of the solution is left behind
Whats the problem with simple distillation?
You can only use it to seperate things with very different boiling points
What is fractional distillation used for?
To seperate out a mixture of liquids
How does fractional distillation work?
The top of the flask is cooler than the bottom ensuring that only the lowest boiling point substance evaporates first as any others that evaporate will just cool and run back down the collumn.
Who thought of the plum pudding model?
JJ Thompson
Who was Ernest rutherford?
He proved the plum pudding model wrong and performed the alpha particle scattering test to show atoms had a nucleus
How was Rutherfords moedel different to Bohr’s model?
He had a field of negatively charged electrons instead of shells with electrons in
What was Bohr’s nuclear model?
He sadi that the atom had shells with electrons in, and none inbetween, his model is the same we have today (although he never theorised about protons and neutrons etc)
What further experiments on the structure of the atom were carried out?
Rutherford proved protons existed
James Chadwick discovered neutrons
Who was dimitri mendeleev?
Mendeleev left gaps in the early versions of the period table for undiscovered elements and also switched some of them if the properties didnt fit the group they were in. His predictions for undiscovered elements were very accurate
What compounds do alkali metals form with non metals?
Ionic
What happens when an alkali metal reacts with water?
The react vigorously
They produce hydrogen
They produce hydroxides (eg sodium hydroxide)
What happens when an alkali metal reacts with chlorine?
They react vigorously and form white salts called metal chlorides
Other than chlorine and water, what else do group 1 metals react with?
Oxygen to produce metal oxides.
How is reactivity arranged in the halogens?
They get less reactive as you go down the group
Describe the properties of Flourine
Very reactive
Yellow gas
Poisonous
Describe the properties of chlorine
Fairly reactive
Dense, green gas
Poisonous
Describe the properties of bromine
Dense, red/brown volatile liquid
Poisonous
Describe the properties of iodine
Dark grey crystalline solid OR purple vapour
How are molecules in the halogens found?
In pairs
How are the melting and boiling points of the halogens affected as you move down the group?
They are found in pairs