Calcium sulfate is ionic or covalent bond

The Lewis structure for the sulfate ion consists of a central sulfur atom with four single bonds to oxygen atoms. This yields the expected total of 32 electrons. Since the sulfur atom started with six valence electrons, two of the S-O bonds are coordinate covalent.

Explanation:

Then that means it has both.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

it's c (engineer's do their work with mechanical stuff not on any living being)