8. Reactivity Trends Flashcards
Group 2 metals are called
Alkaline Earth metal
Reactivity trends increases down group 2
Go down group 2 ionisation energy decreases due to increasing atomic radius and shielding affect
When group 2 elements react the loose electrons, forming positive cations.
Easier to lose electrons the more reactive the element
Group two metals react with water to produce
Hydroxides
Name a metal hydroxide that isn’t really soluble in water
Magnesium hydroxide
Group two metals are used to neutralise acidity give two example
Calcium hydroxide, chalked lime to neutralise acidic soils in agriculture
Magnesium hydroxide and calcium carbonate as antacids in treating indigestion
Group 2 metals burn in oxygen to form
Solid white oxides
Name the structure with giant covalent lattice
Diamond, graphite and graphene
Mettalic binding is the
Electrostatic forces of attraction between metal cations and delicalised electrons
Why do oxides form stronger alkalines as you go down group 2
Oxides(hydroxides) become more soluble down the group
What is the colour of F2
Pale yellow
What colour is chlorine
Green
Colour of iodine
Grey
Why are halogens get less reactive down group
Halogen react by by gaining an electron to form 1- ions
Number of shells increases, sheilding increases and distance from nucleus increases.
Nuclear attraction decreases so harder to attract electrons
Name disadvantages of chlorine
Clorine gas is toxic if breathed
Liqiud chlorine can form chemical burns
They form chlorinated hydrocarbons with organic compound in water which can cause cancer
Benefits of using chlorinein water treatment
Kills desease -causing microorganisms
Some clorine remains in water and prevents reinfection further down
Why do halogens get less reactive down group 2
They are oxidising agents, they react by gaining electrons to form 1- ions
As go down the group atomic radius will increase so outer electrons are shielded more. Less nuclear pull as further from nucleus
Harder for larger atoms to attract electron to form ion( despite increasing nuclear charge)
Test for carbonates
HCl
Test for sulfates
Most summaries she disable in water exept barium sulfate.
So add HCl followed by barium cloride solution
If white precipitate it is barium sulfate
Test for halides
Add nitric acid and than silver nitrate
Silver cloride- white precipitate
Silver bromide-cream
Silver iodide-yellow precipitate
Colour of chlorine water
Colourless
Bromine water colour
Yellow
Iodine solution colour
Orange/brown
Test for ammonium compunds
Add sodium hydroxide to substance and warm.
If ammonia gas is given out. Which can be tested with red litmus paper