UK source on Period 3 oxides:
(It contradicts the text because it states that SiO2 won't conduct electricity as a liquid--molten state--or a solid...bottom of p. 120 in text says molten SiO2 has freely moving electrons...molten form/structure of giant, network covalent structures is not well-established.)

More on SiO2 and carbon allotrope properties: (Seems fairly reputable but not specific to IB...UK Advanced Level represented) (Not sure how reputable...British International School in Bangkok?)

Interactive Learning:

Bitesize learning summary of periodicity of halogens + go to the next page and do a simple simulation of halogen displacement reactions:
(Click the yellow "start" button to start, then click the rubber bulb part of each eye dropper, then click the "next" button to complete the simulation.)

Video Resources:

Practice Tests: