"Is it near?"
In general, you use 近い as the adjective form by itself or talking about the nearness of something
The station is nearby - 駅は近いです
You'll use the adverb form 近く when talking about the nearness in relationship to another object. You usually see it as OBJECTの近く:
The cat is near the bag - 猫は鞄の近くです