# Economic importance of scandium and titanium

> Each use has a reason


## Objectives

- Describe the uses of scandium: a little added to aluminum (MiG fighter jets) and in mercury vapour lamps (TV photography at night).
- Explain why titanium-aluminum alloys are used in aircraft and space shuttles.
- Explain why titanium is used in dental implants and artificial joints (it is inert).
- State that titanium dioxide (TiO2) nanoparticles in sun protection cosmetics prevent the effect of UV on the skin.

## 1. Economic importance of the first transition series




## 2. Why titanium?

Predict: why is titanium used in dental implants?

- It is the cheapest metal
- It is the hardest metal
- It is inert, so the body does not reject it ✓

Titanium is an inert substance: it does not react, so the body does not reject it and it causes no poisoning. That, not hardness or price, is the book's reason for using it in dental implants.

[ar-EG] الـ titanium ده inert substance: مش بيتفاعل، فالجسم مش بيرفضه ومش بيعمل تسمم. وده سبب الكتاب لاستخدامه في الـ dental implants، مش الصلابة ولا السعر.
## 3. Small amounts, big value

Most transition elements are found in small amounts in the earth's crust. But they have high economic importance. The percent of each transition element in the earth's crust (book table) **Scandium** is found in very small amount spread on a large area in the earth's crust.


## 4. 1- Scandium

Adding a **little amount of scandium to aluminum** gives a **light and very hard alloy**. An alloy is a metal mixed with other elements; you'll study alloys later. This alloy is used in MiG fighter jets. MiG fighter jets are made of pure scandium. Scandium's second use Scandium is also added to **mercury vapour lamps**. They give high-quality light that looks like sunlight.


## 5. 2- Titanium in aircraft

Titanium is as rigid as steel, but less dense than steel. Its alloys with aluminum are used in **aircraft and space shuttles**. Reason: it **maintains its durability at high temperatures, while the hardness of aluminum decreases**. Why titanium joins aluminum in aircraft A shuttle must be strong, light and heat-proof. Titanium covers aluminum's weak point: heat.


## 6. Titanium inside the body

fig (1-2): a dental implant made of titanium Inert substance A substance that does not react. The body does not reject titanium, and it causes no poisoning. So titanium is used in **dental implants** and **artificial joints**. Titanium is used in dental implants and artificial joints because it is hard.


## 7. Match the reason

A surgeon fixes a broken arm bone with a metal plate that stays inside for years. Which property makes titanium safe for this? Give a reason: titanium-aluminum alloys are used in space shuttles.


## 8. Titanium dioxide and UV

Remember: UV rays carry more energy than visible light. They can damage the skin. Titanium dioxide: a famous titanium compound Titanium dioxide ($\ce{TiO2}$) is used in **sun protection cosmetics**, where minute **nanoparticles** prevent the effect of UV on the skin. Sun protection cosmetics contain titanium metal.


## 9. Who does what?

Sort each use: scandium, titanium, or titanium dioxide? Titanium is used in artificial joints because it is an ___ substance, so the body does not reject it.


## 10. Summary

Back to the dentist: titanium is chosen because it is **inert**, not just because it is hard. Each use has a reason (book p.5) Implants: **inert**, **not rejected**, **no poisoning**. Aircraft: **maintains its durability at high temperatures, while the hardness of aluminum decreases**. Can you explain why titanium, and not just any hard metal, is used in artificial joints?



Chapter: Transition Elements (https://yaani.ai/ar/learn/chemistry/chem-s3-en.ch1)
Source: https://yaani.ai/ar/lesson/chem-s3-en.lesson-te.uses-sc-ti