"Element array, my dear Watson"

Those of you who have been reading this blog since last year know that one of the things I love about this season is the arrival of the King William's College "Christmas Quiz" (the "General Knowledge Paper").  At the link is the background about the quiz, which hasn't been posted at the school's website yet, or online at The Guardian, but was printed in the paper edition of The Guardian this week.

Here's the fifth set of ten questions.  I've given you a hint re the "theme" for this set.

5. What: 
1. Brings light?
2. Is named for its inactivity ?
3. Has a malodorous tetroxide ?
4. Has a particularly frustrating resistance to corrosion ?
5. Skärgård settlement has shared its name with four examples ?
6. Was named as the daughter of 4, but only shed its alternative name in 1949 ?
7. Was alleged by some to be a pun on its discoverer’s name ?
8. Sounds like some sort of hobgoblin ?
9. Was identified in Lochaber ?
10. Quite simply stinks ?

And here's one more set, which might be misleadingly introduced as "Alimentary, my dear Watson" -

6. What: 
1. Is a deadly oxymoron ?
2. Has insecticide properties ?
3. Could be a cheap form of confectionary ?
4. Grotesque body has achieved a girth of 64 inches ?
5. Two names, applied to a firelighter suggest muscle relaxation and recall kitchen negligence ?
6. Better known as one of Rainier’s features, is the most common source of what favourite hallucinogen ?
7. Sinister form of headgear probably accounted for a Holy Roman Emperor ?
8. Parasite is nominally associated with Iscariot ?
9. Precious stone is deceitful ?
10. Is also a lamellibranch ?

There are 16 more sets of ten questions - most of them much harder than these.  Have a go at these in the Comments if you wish.  I'll withhold the answers for now.

Addendum Dec 18 - Most of these have been solved (see Comments), so I'm adding the fourth set of questions (remember all are related by some common "theme"):

4. Which tale or tales: 
1. Is all about Hester's badge of shame ?
2. Investigates the murder of Robert Ablett ?
3. Describes Lamb's problems in the Banda Orientál ?
4. Relates the heroic story of the survivor from Charybdis ?
5. Describes the criminal activities of Alex, Dim, Georgie and Pete ?
6. Describes a prize fight between the gamekeeper and the coxswain at the Dripping Pan ?
7. Considers the murder of an expat philanderer in east Africa ?
8. Tells of how Dick and the outlaw dress up as friars ?
9. Are set in the moorlands above Tweedsmuir ?
10. Reveals the ghost of a don at All Saints ?

(For this last group, I could have said "A lemon tree, my dear Watson," but that is so tangential that it might mislead people.)

Final addendum - Congratulations to readers of this blog, who correctly answered about 75% of these questions over the past several days.  But now I have to make a change.  The Guardian will shortly be posting the complete quiz, and then thousands of people will be searching the web looking for clues.  It would spoil their fun to find this link with all the answers in the Comments.  So tonight I've deleted all the comments and have closed this post to further comments.