Name the element that form +2, +3, +6 ions and has 4 electrons in highest electron cloud.

The element that forms +2, +3 and +6 ions and has 4 valence electrons is chromium.

Explanation:

As, the given element is showing variable oxidation states, so it is a transition metal only.

So, the element that has 4 electrons in the highest electron cloud and is showing variable oxidation state is chromium.

Electronic configuration of chromium:

Energy of 3d orbital is more than 4s orbital and hence, 4s orbital is filled first although the value of 'n' for 3d is less.

The most stable oxidation states of this element are +2, +3 and +6.

Hence, the correct answer is Chromium.