I have got a silicon standard solution for AAS
So you are saying you have the ready solution? If so, why do you ask how it should be prepared? Somehow I think you didn't wrote what you wanted to, can you elaborate?
a silicon standard solution for AAS is in 2% NaOH. How should I prepare the 2% NaOH? There is not any indication of v/v or w/w or w/v
Sounds like 2% NaOH is just a supporting solution, so its concentration doesn't have to to be too exact, even few percent error won't matter. Difference between 2% w/w and w/v are completely negligible in such case.
Does that easily mean 2 g in 100 ml in measuring flask?
Good analytical practice is to not use measuring flasks for preparation of such solutions - NaOH is corrosive to the glass. I would prepare the solution of NaOH in a beaker.