C3 Flashcards
In the early 1800’s how did they categorise the elements?
By physical/chemical properties
Relative Atomic Mass
Who had the law of the octaves?
Newlands
What was wrong with Newlands table?
His groups contained elements that didn’t have similar properties
He mixed up metals and non metals
He didn’t leave gaps for elements that hadn’t been discovered yet.
In 1869 who organised the periodic table?
Dmitri Mendaleev
How did Mendaleev order it?
In order of atomic mass
Bu the left gaps in order to keep those with similar properties in the same column
Why did Mendaleev leave gaps?
Too allow space for elements that hadn’t been discovered yet
Nowadays how are the elements arranged?
By their electronic structure
What is group 1?
The alkali metals
What happens in group 1?
As you go down -
they become more reactive
have lower melting and boiling points
How many electrons do elements in group 1 have?
1
If a group 1 metal reaction what does it become?
A positive ion
What happens if a group 1 metal reacts with water?
Reacts very vigorously.
Float and move around the surface, fizzing
What do group 1 metal reactions produce?
Hydrogen gas
Hydroxides that dissolve in water to give alkaline solutions
How do you test if a group 1 metal reaction has occurred?
A lighted splint with indicate this by a ‘squeaky pop’
What is group 7?
The halogens
What happens in group 7?
As you go down-
They become less reactive
Have higher melting and boiling points
What are the halogens?
Non-metals with coloured vapours
What colour vapour does fluorine have?
Poisonous yellow gas
fluorine is very reactive
What colour vapour does chlorine have?
Poisonous dense green gas
its fairly reactive
What colour liquid does bromine have?
Dense, poisonous red-brown volatile liquid
What colour vapour does iodine have?
Dark grey, crystalline solid or purple vapour
How do elements in group 7 travel around?
They travel in pairs
What ions do the halogens form?
negative 1 ion
Do the halogens displace eachother?
Yes. More reactive halogens displace less reactive halogens.
