C4 Flashcards
How many elements were known in 1800?
30
What is relative atomic mass?
It is the mass of an element compared to the lightest element hydrogen
who formulated the idea of the modern periodic table?
Dmitri Mendeleev
- he listed elements in order of relative atomic mass, and also left gaps for undiscovered elements in his table. He also noticed that at intervals along the ordered elements were elements with similsr properties e.g. lithium, sodium,potassium share properties
What is the modern periodic table?
What is a general formula equation for group 1 elements reacting with chlorine and how does this reaction occur
-alkali metal +chlorine=salt
the matl burns in the gas producing different colured lights
-leaves colourless precipitate(salt)
What are some compounds of alkali metals?
sodium hydroxide(oven cleaner)
sodium hydrocarbonate
bicarbonate of soda, used in baking
Why are Group 1 metals called alkali meatl?and what are their properties?
as they leave an alkali solution when reacting with water
- corrosive, highly flammable
- very reactive
- reacts with air so kept in oil
- soft metals
- very shiny
- conduct electricity
- less dense then normal metals
What is the foemula equation for an alkali metal reacting with water?
alkali metal+water=hydrogen+an alkali metal hydroxide
What happens to the reactivity of metal as you go down the period in Group 1
It increases
What are the properties of Group 7 elements?
- all very reactive non-metals
- known as halogens
- all diatomic
low melting point , high boiling point
forces between molecules is weak
melting and boiling points as yo go down the table
What are the properties of chlorine,Bromine and iodine?
What are some uses of halogens?
chlorine is used as bleach
clean water
florine is toothpaste
iodine to clean wounds
What happens to reactivity of halogens as you go up the periods?
It increases
What is a displacement reaction?
This where a more reactive halogen replaces the other halogen to form a new compound
HoW can unknown elements be identified?
By burning them and seeing the flame they produce