Limiting an integer in a random matrix

Hi, I want to make a 10 x 10 matrix with values either 1 or 2 but i only want 17 "2's" randomly placed together in 5 separate groups and the rest of the matrix to be "1's".

I was wondering how I should approach this.

thanks

[Azzi Abdelmalek]

placed together : what does that mean?

[José-Luis]

Sounds like homework