Hi there - this is a classical error, which has been answered many times already 
Note that this forum is searchable. E.g.: Zn2+ issues help needed :)
The information about how to define properly ions is also available at:
Hi there - this is a classical error, which has been answered many times already
Note that this forum is searchable. E.g.: Zn2+ issues help needed :)
The information about how to define properly ions is also available at: