reactivity of metals

[evolution]

arrange the following metals in order of their decreasing reactivity:
calcium, gold, magnesium, sodium

give a reason for using gold as a filling for teeth (besides the fact that it looks soooo sexy .....)

[Kishimo]

I think...(not totally sure but i did this in a science lesson recently)

most reactive is magnesium, then sodium, calcium then gold.

Gold is used as a filling for teeth because it is so unreactive.  It won't affect anything.

[NetSquirrel]

Mostly correct - magnesium just goes between calcium and gold. http://www.bbc.co.uk/scotland/education/bitesize/standar d/img/chemistry/metals/reactivity_of_metals/reactivity_s eries.gif

[Kishimo]

Oh yeah! (lol)

Shows how much I pay attention in science =D

[brachiopod]

How many marks for this question?