AS Inorganic Flashcards
periodicity, group 2, group 7 (17)
Where are the spdf blocks located in the periodic table
s- left
p- right
d- centre
f- lanthanides and actinides
What two elements are D block but not transition metals, and why?
Scandium and Zinc. They do not form compounds with partly filled D orbitals
What are lanthinides
group of f-block elements, all similar reactivity, usually form 3+ ions
What are actinides
radioactive f-block metals, only thorium and uranium occur naturally on earth
Why are the melting points and boiling points of Na,Mg, Al and Si higher than the rest of period 3
they form giant structures
why does sulfur (group 6) have a higher boiling point than Phosphorus (group 5)
Sulfur forms S8, so has higher van de Waals forces
Why does atomic radius decrease across a period
increased charge, with no increased electron shielding
Why does solubility of group 2 sulfates decrease down the group?
going down the group, the atoms become bigger, so closer in size to the large SO4 ion. This means that the ions pack together tightly, so there is a high lattice enthalpy, making it more difficult for them to dissolve
Why does the solubility of group 2 hydroxides increase down the group
The magnesium ions are closer in size to the hydroxide ions, meaning that they pack together closely, so the lattice enthalpy is high, and solubilty is low. Going down the group, the size becomes further from the size of a hydroxide ion.
Why is ACIDIFIED BaCl2 needed to test for Sulfate ions
The acid allows CO3 ions to react to form CO2 and H2O, so that carbonate ions cannot form Barium Carbonate which would produce a false positive result
