siktak gaundee gwairi nohyeo isseoyo.

• 놓고 있다 = Active + 있다. It often implies that someone has placed something and is keeping it there or is in the process of placing it.
• 놓여 있다 = Passive/resultative. It simply describes the current state of the object (it has been placed and remains so), without focusing on the agent or ongoing action.

In our sentence, we just want to describe the state of the fruit, so we use 놓여 있어요.

• -에 marks a static location—“at/in/on X,” where something exists or is in a state.
• -에서 marks the place of an action—“do something at/from X.”

Since 놓여 있어요 describes a state of existence (“is placed there”), we use 에. If you were talking about the act of placing, you might say 식탁 가운데에 과일을 놓았어요 (“I placed fruit in the middle of the table”), and you could still use 에 because placing something is targeting that location.

Yes, 식탁 위에 과일이 놓여 있어요 is perfectly correct. Here:

• 위에 = “on (top of).”
• 가운데에 = “in the middle (center).”

So 식탁 위에 과일이 놓여 있어요 means “There is fruit placed on the table,” whereas 식탁 가운데에 과일이 놓여 있어요 adds the nuance that the fruit is specifically in the center of the tabletop.

Yes. Korean word order is relatively flexible for subject and location phrases, as long as the verb stays at the end. Both of these are grammatically correct and mean the same thing:

• 식탁 가운데에 과일이 놓여 있어요.
• 과일이 식탁 가운데에 놓여 있어요.

Choosing one over the other may slightly shift the emphasis—placing 과일이 first can highlight “the fruit” more.