This would be the controversial one, it is both very useful but also deadly.
This is without a doubt the spiteful one due to its radioactivity and use in nuclear weapons.
For example Katie Hopkins could be described as being Uranium in that her opinions can poison other people, her attitude is the fuel, her mouth is her nuclear missile, and the results are her nuclear fallout.
The nice one would likely be Oxygen, it's nice in that breathing it enables us to live, and of course drinking it when combined with Hydrogen, as water is also vital to life.
The lazy, quiet one is definitely Helium because it is the least reactive element and is just about useless.
Helium gives me an amusing image of a lazy, heavy, balding character with an unkempt beard sat sleeping on a chair, with a bunch of helium balloons tied to their arms and legs in an attempt to lift him up. Now if such a character was a loud snorer this would connect to the high pitched voice effect of helium too.
Radium / Polonium
The radioactive elements Radium or Polonium would be the tragic one due to them being discovered by Marie Curie which among the other radioactive elements she worked with, led to her death. [source]
The loud one would be Potassium or one of the Alkali metals. This is because Potassium nitrate makes up 75% of of gunpowder's composition [source]. Potassium also reacts violently in contact with water. [source]
Sulfur would be the weird or gross one due to its sickly yellow colour and horrible rotten-egg like smell. [source]