Can anydody explain why only two out of my 7 hubs are indexed by google and rest are unvisible.

You have only been on Hubpages for a short amount of time. I would say 2 being indexed is not a bad start but with your skills and Hubpages I would think more would be available to view.

In my experience some hubs hit hard right away an some just take some seasoning. Maybe give it a few days and see if things change as far as traffic and indexing.

If you dont see a change in the near future I would consider changing the title around to make it search engine friendly. I change my titles if I dont get the response I expect and sooner or later I find the right combination.Make sure the first paragraph or sentence hits home for your target keyword phrase.

I hope this will help you. This method of marketing articles or (hubs) has made a big difference for me.

For me , I always try to use the title in my first sentence or two in a subtle way to attract the search engines.

I also use LSI keywords which is the way most search engines these days have adjusted to keyword stuffing.