I'll tackle one, probably the worst one on the list: elemental fluorine.
You can tell who all the sensible chemists are because they have suddenly left the room. The more adventurous ones stay for the fireworks, but have Hazmat on speed dial. Wikipedia mildly explains their concern.
Reactions with elemental fluorine are often sudden or explosive.
Elemental fluorine reacts very exothermically with every other element except neon and helium. It reacts with sand. It reacts with brick. And all at room temperature! Here's a video of that.
This stuff is desperate for electrons, but it won't react with glass... unless your glass is at all wet (and most has some water trapped) in which case it rips away the hydrogen to create hydrogen fluoride, which becomes hydrofluoric acid in water, and it eats through the glass.
If you're "lucky" (50/50 chance) it will eat through the front, back, or top and vent into the room. Now you're "only" worried about hydrofluorine gas. I say "lucky" because it will likely disperse before it can eat through the glass into any of the other elements. For anyone or anything else in the room... well, here's how chemist Derek Lowe of In The Pipeline describes an experience with HF...
It gives terribly painful burns, and it eats through glass, to pick two of its fine qualities. But if you’re going to be precise, hydrofluoric acid is a water solution of hydrogen fluoride, HF. That’s a gas, and it’s a lot worse.
Actually, it’s just barely a gas. In a cool room it’ll condense out as a liquid (it boils at about 20 degrees C, which is 68 F.) The straight liquid must really be a treat, but I’ve never seen it in that form, and would only wish to through binoculars. It’s sold compressed in metal cylinders, like other gases, but it needs some care in packaging. The stuff is so corrosive that special alloys need to be used, usually ones high in nickel. If you stick an ordinary gas regulator on top of an HF cylinder, you’re in for trouble, and the complete destruction of the regulator is the least of your worries.
...The shout “HF LEAK!” went out into the halls, and I’m told that the whole area set a never-to-be-equaled evacuation record. This was one of those drop-things-right-where-you-stand type evacuations, a real sauve qui peut moment.
As bad as HF is, the compounds it can make with other elements are far, far worse. Derek goes on about some of the worst in great detail and from inside a fume hood in the building across the street. Let's say the HF breaks through to a neighbor, what are its options?
One of the few things fluorine does not react with, you lucky skunk.
This, plus the 50% chance it will vent into the room, gives you 66% chance of surviving the day! Because nothing good happens for the remaining two choices.
Chlorine gas is already used as a chemical weapon, and fluorine can only make things better! Did I say better? I meant horribly worse!
At room temperature you get ClF or Chlorine Monofluoride which reacts with metals, but not glass. But since all fluorine reactions are very energetic, and this is happening in a small enclosed space, it may get hot enough to provide some "fun" stuff, ClF3 or Chlorine Trifluoride!
Derek talks about ClF3 in the ominously titled "Sand Won't Save You This Time", here's some choice quotes:
It is apparently about the most vigorous fluorinating agent known, and is much more difficult to handle than fluorine gas. That’s one of those statements you don’t get to hear very often, and it should be enough to make any sensible chemist turn around smartly and head down the hall in the other direction.
The compound also a stronger oxidizing agent than oxygen itself, which also puts it into rare territory. That means that it can potentially go on to “burn” things that you would normally consider already burnt to hell and gone, and a practical consequence of that is that it’ll start roaring reactions with things like bricks and asbestos tile.
There’s a report from the early 1950s of a one-ton spill of the stuff. It burned its way through a foot of concrete floor and chewed up another meter of sand and gravel beneath, completing a day that I’m sure no one involved ever forgot. That process, I should add, would necessarily have been accompanied by copious amounts of horribly toxic and corrosive by-products: it’s bad enough when your reagent ignites wet sand, but the clouds of hot hydrofluoric acid are your special door prize if you’re foolhardy enough to hang around and watch the fireworks.
You can safely assume if ClF3 forms the rest of the case is toast.
Alas, you won't get FOOF at room temperature without electricity being introduced, but you can read Derek's descriptions anyway.
...you run a mixture of oxygen and fluorine through a 700-degree-heating block. “Oh, no you don’t,” is the common reaction of most chemists to that proposal, “. . .not unless I’m at least a mile away, two miles if I’m downwind.”
I'm not sure what fluorine and oxygen produce at room temperature. It's probably extremely energetic and may melt the glass releasing two of the most vigorous reactants into more elements!