Chem Unit 2 (Grioup 2) Flashcards
The reducing abiltiy of the group 2 elements means they can reduce water to..?
hydrogen
In group 2 the metal si therefore..?
oxidised
Down group 2 the atomic radius..?
increases>increases shielding>outweight effect of nucleur charge
Down group 2 first ionisation energy..?
decreases>successive shell>more shirlding>easierto remove
In group 2 it is … bonding and each metal ion loeses…?
- metallic
- 2 electrons t sea of delocalised electrons
The trend in melting points of Group 2 elements is generaally a ..?
decrease (exception from Mg>Ca)
- Each metal ion has 2 delocalised electrons
- Each successive shell adcded with each electron
- more inner shielding/larger ionic radius
- less strong attraction to the nucleus
- takes less energy to melt most of the bonds
Magnesium metal is oxidised so..?
Mg > Mg2+ + 2e-
0 > 2+
Water is reduced to hydrogen so..?
2H20 + 2e- > 20H-
If the Group 2 metal is added to cold/hot water then..? (Hot water will make reaction go less quick than cold water)
Mg + 2H20 > Mg(0H)2 + H2
If the metal reacts with steam the reaction is …? and more… is produced.
-exothermic
-more H2 is produced
Mg + H20 > Mg0 + H2
A solution is a mixture of ..?
solute and solvent
The solubility of a soltion in the maximum
concentraation of the solution possiblr
Uses of group 2 metal hydroxides?
Mg(0H)2- useful to neutrilsie stomach acid
Mg(0H)2 + 2HCL > MgCl + H20
Ca(OH)2 - slaked lime- used to neutriise soil acidity
OH- + H+ > H20
The pattern of sulphates and hydroxides (group 2)
As you go down from Be>Ba
- the group 2 sulfates decrease down the group
- the group 2 hydroxides increase in solubility down the group
- ALWAYS a white precipitate
Why can barium sulfate be used to show x-rays?
because although barium is poisonous, barium sulfate is extremely insoluble so it can pass through the body without dissolving in any of the body fluids
Ability to absorb x-rays means it can produce an image for medical prroblems
