निम्नलिखित में से कौन सी 3d-संक्रमण धातु उच्चतम ऑक्सीकरण संख्या प्रदर्शित कर सकती है?

The correct decreasing order of basic character of the given transition metal monoxides is:

In which of the following pairs do both elements NOT have the (n-1)d10ns2 electronic configuration?

In the following pairs, the one in which both transition metal ions are colourless is: