Do all imperitives sentences have periods at the end?

No, imperative sentences don't always have periods at the end. Here's why:

* Imperative sentences are commands or requests. They tell someone to do something.

* Punctuation depends on the strength of the command.

* Periods (.) are used for gentle or neutral commands. Example: "Please close the door."

* Exclamation marks (!) are used for strong commands or urgent requests. Example: "Stop! You're in danger!"

Here's an example:

* Gentle request: "Pass the salt, please." (period)

* Strong command: "Get out of the house!" (exclamation mark)

So, while imperative sentences often end with periods, they can also end with exclamation marks depending on the intended tone.