he difference between a container tag and an empty tag is quite simple. a conatiner tag is the one which has to be closed and an empty tag doesnt need to be closed.
for example:
CONTAINER TAG
<html> is the opening tag
</html> is the closing tag
<a href=""> is the opening tag
</a> is the closing tag
(closing is required)
EMPTY TAG
<img src="">
<br>