Decrease from left to right of period 3 with water

HOWEVER

Cl₂ reacts with water 

Cl₂(g)+ H₂O(l)---> HCl (aq)+ HOCl(l)

Reativity increass down group

Be has no rxn with water

Ca(s)+ H₂O(l) --> Ca(OH)₂(aq) +H₂(g)

Solubility of SULPHATES down the group 2?

(PLEASE REMEMBER)

Decrease in solubility down the group 2.  

Solubility affected by ndothermic lattice enthalpy and exothermic enthalpy of hydration. The more exothermic the overall rxn then the more soluble the products! Enthalpy of hydration decreases down group 2 while lattice enthalpy relatively constant due to large size of sulphate. 

Get it. Set it. Don't Forget it...once group 2 on exam paper...this is more than likely on it!!!!!!!!!!!

stability increases down the group

takes in consideration endo lattice enthalpy and exo enthalpy of formation

CaCO₃(s)--> CaO(s)+ CO₂(g)

Na₂O forms NaOH which is completely soluble in water and thus dissociates completely 

MgO forms Mg(OH)₂ which is barely soluble in water thus does not dissociate as readily to release OH^- ions.

Therefore the former is the stronger base.

Why is BaSO₄ acceptable when X-ray analysis  though Ba²⁺ ions are toxic? 

CAPE question of 2007

treating drinking water

shell of lobster 

Ionization energy decreases down the group 

because IE inversely proportion to atomic radii which in this group increases down the group.

Explain relative stability  of oxides of group 4 elements of oxidation states +2 and +4.

CAPE question 2003  worth 4 marks :P

Relative stability of +4 oxidation state decreases down group and thus +2 increases down the group as highlighted clearly with Pb which is most stable as PbO.

Take in consideration the thermal decomposition of the group 4 dioxides...all stable EXCEPT PbO2 which decomposes to give PbO

Reaction of lead (IV) oxide with sodium hydroxide

Is the reaction similiar for Sn?

PbO_{2 (s)}+ 2NaOH(aq)--> Na₂PbO₃ (aq) + H2O(l)

Yep real similiar

Na₂SiO3(aq) only difference in product

Reaction of lead (IV) oxide with  a concentrated acid (like HCl)

clue (similiar rxn of Sn)

SnO(s)+ NaOH(aq)+ H2O(l)--> NaSn(OH)₃ (s)

H2O of the NaOH solution reacts with SnO 

SiCl₄(l)+ 2H₂O(l)--> Si(OH)₄+ 4HCl(aq)

but then Si(OH)₄--> SiO₂(s)+ H₂O(l)

Thus:

SiCl₄(l)+ 2H₂O(l)--> SiO₂(s)+ 4 HCl(aq)

Account for this: When exposed to the atmospher, SiCl₄ produces white fumes while no such fumes are produced with CCl₄?

CAPE question 2010 

 that  part of the question worth 5 marks in total.

SiCl4 is hydrolysed to silicon (IV) oxide and HCl gas with the water in the atmosphere due to presence of vact d sub shell...the fumes seen is a mixture of the white precipitate of the oxide and the colourless fumes.

C of CCl4 has no d subshell much les a vacant one and thus a lone pair of the oxygen of water could not form a dative covalent bond with it and hydrolysis would and could NOT occur.  

Decrease in ease of hydrolysis down the group as metallic character increases. 

CCl₄ does not take part in hydrolysis due to absence of empy d orbitals.

It has been observed that a solution of aqueous chromium (III) ions, [Cr(H2O)6]³⁺ (aq) is weakly acidic. Suggest an explanation for this observation?

CAPE question 2006

Marks 2

First and foremost...all cations of transition metals in complexes are Lewis acids as they attact lone pairs  from their ligands.

Secondly, all 3+ oxidation state aqua transition ions are more acidic than 2+ due to their high charge density in comparison to others.

Variable oxidation state

This allows them to act as intermediates in reactions.