parallel structure

English as a Second Language English Vocabulary, Grammar and Idioms
1

An instructor uses a marker pen to write on the whiteboard while a chalk is used to write on the black board.

Is this sentence parallel structure? ‘used’ is in past tense.
Can anyone suggest a sentence that is parallel structure?

2

Here are your fixes:

An instructor uses a marker to write on the whiteboard and chalk to write on the blackboard.

Markers are used on the whiteboard, while chalk is used on the blackboard.