Đặt CT chung: \(Cu^{II}_a\left(NO_3\right)_b^I\left(a,b:nguyên,dương\right)\)
Theo QT hóa trị, ta sẽ có:
II.a=I.b <=> a/b= I/II=1/2 => a=1;b=2
=> CTHH: Cu(NO3)2
\(PTK_{Cu\left(NO_3\right)_2}=NTK_{Cu}+2.NTK_N+3.2.NTK_O=64+14.2+6.16=188\left(đ.v.C\right)\)