Studied by 2 people
What is an element?
pure substance that consists entirely of one type of atom
How many elements do we know of?
118
What are physical properties of metals?
High melting & boiling points, good conductivity, high density, shiny, malleable
What are chemical properties of metals?
Positive ions, form basic oxides
What are physical properties of non-metals?
Low melting points, poor conductors of heat/electricity, low density, brittle
What are chemical properties of non-metals?
Form oxides that are acidic, react to form molecules, negative ionisation (generally)
What is a compound?
substance formed by the chemical combination of two or more elements in definite proportions
What type of compound is formed in the reaction of two non-metals?
molecular compound
What type of compound is formed in the reaction of a non-metal and a metal?
ionic compound
What are the Noble gases?
Group 0
Why are noble gases inert?
They are in group 0, therefore they have a full outer shell, so they are stable and do not need to gain or lose electrons.
What are group 1 metals called?
alkali metals
What is special about group 1 elements as metals?
Low boiling points, low densities, soft
What ions do alkali metals form?
1+ ions
What do alkali metals form when reacting with oxygen?
White metal oxides
What do alkali metals form when reacting with water?
Metal hydroxide + Hydrogen gas
What do alkali metals form when reacting with halides?
Metal halides
Why does reactivity increase as you go down group 1?
There are more energy levels so the valence electrons are further out, have more energy and are less attracted to the nucleus. This means they are easier to lose so the metal is more reactive.
What are group 7 elements called?
Halogens
What is special about how halogens exist naturally?
They are diatomic molecules
Properties of halogens?
Poisonous, coloured gases, can form covalent bonds and ionic bonds.
What is the reactivity trend of the halogens?
They get less reactive down the group
Why can Fluorine displace Bromine?
It is more reactive
What are transition metals?
The elements between groups 2 and 3
What is special about transition metals?
can have more than one ion
often colourful
Usually good catalysts
What did John Newlands do?
Law of Octaves, he realised that for the first 16 elements, every eighth had similar properties.
How did Newlands organise his periodic table?
By atomic mass
What did Mendeleev do differently?
Left gaps where the properties didn't quite fit and altered the order if properties fit better elsewhere.
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