Are all scientists are inventors?

Definitely not. A scientist is a person that engages in a systematic activity to acquire knowledge. Or someone who engages in practices and traditions that are linked to schools of thought or philosophy. An inventor is a person who creates or discovers a new method, form, device or other useful means. A lot of inventors are scientists but an inventor doesn't have to be a scientist to invent something. In return a scientist doesn't have to invent anything.