Noun:
* The artist used a slate to draw a picture. (Slate as a flat piece of rock)
* The school board is planning a slate of educational reforms. (Slate as a list of candidates or items)
* The roof is made of slate tiles. (Slate as a roofing material)
Verb:
* The candidate is slated to speak at the rally. (Slate as to schedule or plan)
* The magazine slated the new film for its poor acting. (Slate as to criticize)
The sentence you choose will depend on the context and the meaning you want to convey.