Periodic Table
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How many elements are there How many occur naturally
118 94
What is the trend of G1 Reactiviy Softness Density Melting+boiling
Increases down the group Increases Increases Decreases
Why are they called alkali metals
When reacted with water they form an alkaline solution
Physical properties of alkali metals(2)
Relatively soft Relatively low density and melting points Tarnish?
What is the general formula for G1+water
Metal+water=metal hydroxide+hydrogen gas
What is lithiums reaction with water
It floats as it is less dense, there is effervescence and it moves around due to the hydrogen gas being given off Dissolves to form aqueous solution of LiOH
How does sodium react with water
Melts, floats, moves around on surface vigorously, effervescence and hydrogen gas Dissolves to form NaOH
How does potassium react with water
Enough heat is produced to light the hydrogen gas and a lilac flame is produced, hops around
Explain the trend in reactivity of G1
The more easily the valence electron is lost the more reactive it is, the further down the group, the bigger the atom, the further away the electron is to the nucleus, the smaller the electrostatic attraction
What was the first halogen to be discovered and where was it used
Flourine, in mineral fluorospar in ceramics
How was chlorine extracted/discovered
From hcl
How was bromine extracted/discovered
Bubbling chlorine gas through water sample
How was iodine extracted/discovered
Burning seaweed and treating the ashes with sulfuric acid to produce a purple vapour
How was astatine extracted/discovered
Bombarded bismuth with radiation
Use of chlorine
To disinfect
Use of bromine
To disinfect
Use of Florine
To help medical drug enter cells
Use of iodine
Prevent infection
Use of satiating+all halogens
Energy efficient lamps
Why is GVII called halogens
It means salt producing, when reacted with metals salts are produced
What is the trend for colour in GVII + state fl,cl,br,I
Darkness decreases down Yellow-green gas Green gas Red liquid Dark purple solid
Trend of GVII Density Melting points Reactivity
Increase Increase Decrease
Explain the reason for the trend in reactivity in GVII
Hal go gens have 7 valence electrons and react by attracting other electrons to fill their outer shell. As you descend down the group, the number of shells increase and the ability to attract the electrons decreases
What happens When a more reactive element comes into contact with a less reactive element in a compound
A displacement reaction