Question

what should students notice about the structure of elements as they form molecules? carbon forms chains, and phosphorus, nitrogen, and sulfur are often found in the middle of chains. phosphorus exclusively forms linear chains. hydrogen is always at the center of molecular chains. all elements form circular molecular structures

Explanation:

Carbon has the ability to form long chains (as seen in the protein - like structure with repeated units and in organic molecules). Phosphorus does not exclusively form linear chains (as shown by the phospholipid structure which is part of a membrane - like structure, not just a simple linear chain). Hydrogen is not always at the center (e.g., in the sugar molecule, carbon is a central atom). Not all elements form circular structures (e.g., the linear - like structure of the protein - like molecule).

Answer:

Carbon forms chains, and phosphorus, nitrogen, and sulfur are often found in the middle of chains.