Properties and uses of metals L.O: To know the location of the transition metals in the periodic table, and know what their properties are. To understand that the properties of metals make them useful for many different uses. Wednesday, 19 September 2018Wednesday, 19 September 2018

Basic Properties of Metals Most of the elements are metals — so they cover most of the periodic table. In fact, only the elements on the far right are non-metals

Basic Properties of Metals All metals, including transition metals, have some fairly similar basic properties: They are strong (hard to break). They can be bent or hammered into different shapes. They're great at conducting heat. They conduct electricity.

Basic Uses of Metals Metals (and especially transition metals) have loads of everyday uses because of these properties... Their strength and ‘bendability' makes them handy for making into things like bridges and car bodies. Their ability to conduct heat makes them ideal if you want to make something that heat needs to travel through, like a saucepan base. Their electrical conductivity makes them great for making things like electrical wires.

Copper, Aluminium, and titanium Not all metals are the same — you need to learn the specific properties of copper, aluminium and titanium. Copper: Copper is a good conductor of electricity. It's hard and strong but can be bent. It also doesn't react with water. Aluminium: Aluminium is corrosion-resistant and has a low density — this low density means that it's lightweight. Pure aluminium isn't particularly strong, but it forms hard, strong alloys. Titanium: Titanium is another low density metal. Unlike aluminium it's very strong. It is also corrosion-resistant.

Uses of Metals Different metals are chosen for different uses because of their specific properties. Use the table to answer the questions on the next slide…

Uses of Metals …And why? Metal RelativeDensity Strength Conducts electricity? Malleable? Will it corrode? (with H2O) Copper Medium Strong Yes No Aluminium Very low Not very strong Not normally Titanium Low Very strong Not well Not much Which metal would you use for water pipes? Which metal would you use for electrical wires? Which for an aeroplane body? Which would you use for replacement hips? …And why?

Uses of Metals If you were doing some plumbing, you'd pick a metal that could be bent to make pipes and tanks, and is below hydrogen in the reactivity series so it doesn't react with water. Copper is great for this. If you wanted to make electrical wires, you'd pick a metal that is a good conductor of electricity and can be drawn out into wires. Copper is an ideal choice for this. If you wanted to make an aeroplane, you'd probably use metal as it's strong and can be bent into shape. But you'd also need it to be lightweight, so an aluminium alloy would be a good choice. If you were making replacement hips, you'd use a metal that won't corrode when it comes in contact with water. It'd have to be light and not too bendy. Titanium has all of these properties so is used for this.

Uses of Metals Metals are very useful structural materials, but some corrode when exposed to air and water, so they need to be protected — for example, by using paint. If metals corrode, they lose their strength and hardness. Metals can also get ‘tired' when stresses and strains are repeatedly put on them over time. This is known as metal fatigue and leads to metals breaking, which can be very dangerous. For example, in planes it's really important that metal components aren't fatigued so they are safe during flights. To help prevent fatigue, metal parts are specially designed and regularly checked.

Questions – Fact Recall Give the letter that corresponds to the transition metals on this periodic table. Metals are good at conducting electricity. Suggest one metal product in which this property is important. Give two other basic properties of metals. Aluminium alloys are used to make lots of aeroplane parts. Why are they suitable for this use? Give two reasons why copper is ideal for use in plumbing. Which properties of titanium make it a suitable metal for replacement hips? Give two disadvantages of using metals as structural materials.

Questions - application Anniel is buying a new bicycle. She can buy either a steel, aluminium or titanium frame. This table shows some properties of these metals. She would like a bike that's not too heavy or expensive. Use the table to suggest a type of frame for Annie and give reasons for your choice.

Answers – Fact Recall B E.g. electrical wiring. Any two from: e.g. They are strong/hard to break. / They can be bent into different shapes. / They are good conductors of heat. They are strong and have low density/are lightweight. It can be bent into different shapes (like pipes) and doesn't react with water. It's not too bendy, it's light and it doesn't react with water. Metals can corrode when exposed to air and water. Metals can also suffer from metal fatigue which can cause them to break.

answers - Application E.g. Annie should buy an aluminium frame. Aluminium has a very low relative density so it's very lightweight. It's also highly resistant to corrosion so won't corrode when it gets wet, and it's quite strong. It isn't the cheapest type (steel) but it isn't the most expensive either (titanium). Titanium shares similar properties to aluminium but it's more expensive. For this question you might have chosen a different type of frame that Annie should buy. That's fine as long as you've backed up your choice with good reasons.