The chemical formula for mercury(II) nitrate is Hg(NO₃)₂.

Here's how to break it down:

* Hg: This represents the mercury element. The Roman numeral II indicates that mercury has a +2 charge.

* NO₃: This represents the nitrate ion, which has a -1 charge.

* (NO₃)₂: Since nitrate has a -1 charge, and mercury has a +2 charge, you need two nitrate ions to balance the charges.