Metals

[curie]

Sorry if this has been posted before.
I did a search and couldn't find it.
I've just beeen printing out a bunch of labels for metals from chemffx and have noticed that magnesium and zinc show
"do not add water" . We often use metals for testing reactivities in solution and pop tests. Are these tests now outlawed? Can somone shed some light on this?

[dime]

This would be for powdered zinc and magnesium, I would think. Powdered metals are 4.3 and therefore react with water.