Chapter 4: Metals Flashcards
List and describe the general properties of metals
- have relatively high boiling and melting points
- are good conductors of electricity
- are good conductors of heat
- generally have high densities
- are malleable (can be shaped by beating or rolling)
- are lustrous (reflective when cut or polished)
- are ductile (can be drawn into a wire)
- low ionisation energies and electronegativities (ready to lose electrons)
- high tensile strength (a measure of the force needed to break something or cause it to fail)
Describe the metallic bonding model
The metallic bonding model is a lattice (a tightly packed arrangement). Cations are surrounded by a sea of delocalised electrons.
In relation with the metallic bonding model, describe the properties of metals.
- high boiling and melting points: Strong electrostatic forces of attraction between positive metal ions and the sea of delocalised electrons holds the metallic lattice together.
- conducting electricity: Free moving delocalised electrons will move towards a positive electrode and away from a negative electrode in an electric circuit
- malleable and ductile: When a force causes metal ions to move past each other, layers of ions are still held together by the delocalised electrons between them.
- high density: The cations in a metal lattice are closely packed.
- conductors of heat: When the delocalised electrons bump into each other and into the metal ions, they transfer energy to their neighbour.
Heating a metal gives the ions and electrons more energy and they vibrate more rapidly. The electrons, being free to move, transmit this energy rapidly throughout the lattice.
What is an alloy?
A substance formed when other materials are mixed with a metal
How do we determine the reactivity of metals?
To determine the relative reactivity of each metal you can look at what happens
when they are exposed to water, oxygen or acids.
What product is created when a metal reacts with water?
When metals react with water, generally a metal hydroxide and hydrogen gas is formed.
What product is created when a metal reacts with oxygen?
When metals react with oxygen, metal oxides are formed.
What product is created when a metal reacts with acids?
When metals react with acids, hydrogen gas and salt is formed.
Describe the process of obtaining pure metal from an ore.
- Mining: Open-pit mining (removing surface vegetation, soil and bedrock to reach the ore below the Earth’s surface), underground mining (dig vertical shaft into the ground), leaching (solutions injected into holes in ore deposit to dissolve the minerals and resulting solution is pumped to the surface to recover the minerals)
- Ore processing: Open-pit mining (removing surface vegetation, soil and bedrock to reach the ore below the Earth’s surface), underground mining (dig vertical shaft into the ground), leaching (solutions injected into holes in ore deposit to dissolve the minerals and resulting solution is pumped to the surface to recover the minerals)
- Metal extraction: Electrolysis (using electric current) typically used to extract very reactive elements.
Or Smelting - Ores are first roasted in air to convert them to metal oxides then heated to high temperatures with carbon (smelting).
What are some environmental issues with obtaining pure metal from an ore?
- land
- soil
- air
- biodiversity
Compare linear economy and circular economy
In a linear economy, raw materials in the form of natural resources are used to make a product and after its use the article is ultimately thrown away. This type of economy is often described as operating with a ‘take-make-dispose’ or a ‘take-make-waste, model
An economy based on a model of production and consumption that aims to design out waste and pollution, keep products and materials in use, and regenerate natural systems
