What are the respective central-metal oxidation state,coordination number,and overall charge on the complex ion in Na₂[Cr(NH₃)₂ (NCS)₄]? A)+3; 6; -1 B)+3; 6; +1 C)+2; 6; -2 D)+2; 4; -1 E)+1; 6; -2

Question

Quizplus · Accepted Answer

The complex ion is [Cr(NH3)2(NCS)4]. 
The oxidation state of chromium is +2 since there are four negative charges from NCS ligands and two positive charges from NH3 ligands. 
The coordination number is 6 since there are six ligands coordinating to the central metal atom. 
The overall charge on the complex ion is -2 since there are four NCS ligands, each with a charge of -1. Therefore, the best choice is C.

What Are the Respective Central-Metal Oxidation State,coordination Number,and Overall Charge