An accordion always contains the category title, an expanded and a collapsed state, an icon indicating expansion, and the spacing between them.
It should be used when users only need a few key concepts or descriptions of the content on a single page.
It happens that the open card was closed, to give way to the information of the next open card, but there are different designs that prefer it the other way around.
You must choose a different icon to open and close, so that the user understands what action he took.