What element forms an ion with an electronic configuration of 1s22s22p63s23p63d104s24p64d105s25p6 (or [xe]) and a –2 charge?

Explanation:

Atomic number of Xenon is 54 and its electronic configuration is .

When an element gains an electron then it acquires a charge of -1. And, when two electrons are gained by an element then it acquires a charge of -2 and so on.

Tellurium is the element which has 52 electrons and electronic configuration of is as follows.    

Thus, we can conclude that tellurium element forms an ion with an electronic configuration of and a charge of -2.