Are they all the same type of seed in the flat?

If so....

They will germinate in a few days as normal, and after a week or so, you could call the seeds 'duds' if they don't germinae

Domes are helpful when germinating (for most things), but they are not necessary.

Keriann~

Since you jumped all over other posters for not posting they way you 'wanted', please don't be offended if others pass up advising you now. Just an FYI

Here is one of several previous discussions of this question that should answer your question.

Dave

Here is a link that might be useful: remove cover and put under lights if only few have germinated?