Final answer:
Titanium is the transition metal used for creating strong, lightweight items like golf clubs and artificial joints, due to its excellent strength-to-weight ratio and corrosion resistance.
Step-by-step explanation:
The expensive transition metal often used to make strong yet lightweight items such as golf clubs and artificial joints is titanium. Titanium is known for its high strength-to-weight ratio and corrosion resistance, making it ideal for manufacturing lightweight, durable products. Among the options provided, platinum, palladium, and rhodium are all considered platinum metals, which typically do not form stable oxyanions and have other specialized uses. However, titanium's properties are particularly well-suited for applications that require both lightness and strength, such as sports equipment and biomedical implants.