First of id like to say im a beginner so any help is welcome 
Im using corona chaos as plug in and when i chaos scatter i see these spots that are not filled with grass and no metter how much i add count it cannot be filled
Hi, welcome!
What you’re experiencing is normal/expected.
2 options I can suggest:
- more density/higher scatter count will help but this might becomes too heavy so not an ideal solution.
- just apply a green/grass material to the the surface you’re scattering on - this will hide the gaps a bit. But in reality as the material will be soil, this might be even better - to add a bit of realism as often grass isn’t perfect. In fact, if viewing the grass from eye-level these gaps won’t be noticeable anyway. Aerial views will of course show these gaps.
All the best!
I have some hints here:
- Always use large grass clumps as the scattered model. Don’t use clumps of just a few blades, and never ever use a single grass blade.
- Enable “avoid collisions”, but lower the spacing to about 20-50%
- Reduce the “from” scale. In the example below I used scaling from 10% to 100%. This fills the “holes” with those smaller instances.
And do the ground texturing.
Fun fact – Why is neighbor’ grass always greener? Because you can’t see empty patches from the side. 
Corona - physical AND psychological realism