Which google scholar citation format is IEEE standard?

None of the "standard" citations that they provide is IEEE format.

Instead, you should use one of the links at the bottom to take the format for your preferred citation manager, such as BibTeX, which can then be used to format following any publication venue's guidelines.

For IEEE in particular, the best option is generally BibTeX, because IEEE strongly pushes its authors towards preparing their publications via the IEEE LaTeX package and its accompanying BibTeX style format.

Word supports the IEEE citation format already (at last Word 2016).

I would suggest using JabRef to build a BibTeX-file to keep track of your references. JabRef can export to the reference list format Word supports (an XML-file). It can also directly import the BibTeX-entires downloaded from Google. I suggest this program, as the built-in reference list editor in Word is nearly useless. Another alternative, if you are on Windows, is to use bibtex4word. This macro uses MikTeX or TeX Live to generate a reference list from your BibTeX-file which is subsequently imported into your Word document.