Chapter 4- Metalliac Bonding Flashcards
Define a Metalliac Substance
They are made up of an array of cations in a sea of electrons
What are the properties of a metalliac substance?
- Lustrous
- Good conductors of heat and electricity
- Malleable
- Ductile
- High Density
- Various melting points (most high)
- Do not break easily
Explain metals lustre
The lustrous appearance is from the free moving electrons being able to reflect the light.
Explain metals high melting point/hardness
Usually shows that the metalliac bond is strong
Explain metals malleablity and ductility
They have a non-directional nature. They can pass one another without aggravation. Properties do not change when they become thinner.
Explain metals conduction of heat
- Electrons gain kinetic energy and move from hot to cold areas of the metal.
- Heat causes electrons to move faster
- Hence they bump into eachother
- The bumping transfers heat
Explain metals conduction of electricity
Electrons move towards a positive charge, so there is a flow of electrons, this is called an electric current.
What is an alloy metal
An alloy is a metal that has various metals mixed in with one another, some including non-metals.
Do the properties of an alloy change from the original metal?
Yes
Define Subsitutional Alloy
If both of the metals have roughly the same atom size then the can replace eachother in the crystal lattice
Define Interstital Alloy
When two combining metals have a great variation in atom size, therefore smaller atoms fit between the larger ones.
Explain briefly the properties of each block (s,p,d,f)
s- very reactive, low density, low melting point, usually make compounds that are white
p-metals, non-metals, metalloids properties vary
d- transition metals, make compounds that are coloured, good catalysts
Explain the Ball Bearing Model
- When a metal bends atoms are sliding over one another
- The more easily they slide the more easily the metal will bend
- perfect rows = bending distored rows= no bending easily
What is worked hardening?
Modifying or bending physically cold metals causes work hardening.
-Metal becomes tougher and it cannot bend back into its original shape
What are the three ways that metals can be modified usuing heat
- Anneal
- Quenching
- Tempering
Define Annealed and explain product
Heated until red hot then cooled down. This results in a larger and softer molecule, as well as restoring ductiblity.
Produces a softer metal
Define Quenched and explain product
Heated untill red hot then immediately placed in cold water. Small and brittle crystals are formed
Define Tempered and explain product
Quenched metals that are warmed again to a lower temperature and then allowed to cool slowly.
-Product will have reduced brittleness thus allowing it to maintain its hardness
Properties, uses and reactivity of the s-block.
- Alkai metals are very reactive, mostly found in compounds
- Alkali metals have a low density and a low melting point.
- Alkaline earth metals are less reactive, harder, and will have a higher melting point than the alkali metals.
- Both groups usually form compounds that are white
Specific uses and properties of the p-block metals
The p block contains metals and non-metals. The properties of the metals vary
Specfic uses and properties of the d-block
- Form coloured compounds.
- Most are used in the form of alloys
- Often used as catalyst
Why are alloys useful?
Alloys are useful as metals such as sodium cannot be used on its own due to it’s high reactivity. However when alloyed with other metals, it can have very many useful purposes.
How are alloys prepared?
Melting the metals or other materials together and cooling the mixture.
Specfic uses and properties of the f-block
Mainly radioactive
What is the purpose of surface protection
Provent air and water from coming in contact with the metal. e.g plastic, paint, grease
Nobel Coatin
A coating using a metal that is less reactive than steel, it serves purely as coating.
What happens with nobel coating is scratched
Rapid corrosion of the exposed steel.
Why can’t zinc be used as noble coating?
It is posionous to the human body therefore husehold items are plated with tin and chromium.
Sacrifical coating
A coating using a metal that is more reactive than steel.
What occurs in a break in sacrifical coating
Formation of an electrochemical cell, the coating corrodes and the steel is protected. Zinc is the most common form/
What influences the extraction of metals
The reactivity of metals
Extraction of iron: The blast furnace
- Rock is crushed into fist size pieces o rock
- Rocks are heated
- Calcium carbonatie is added to reduce the iron oxides
- A mixture of iron ore, coke and limestone is added at the top of the furnance
- Hot air is blasted through
- Iron falls to the bottom of the furnace
Environmental Impacts of iron production on society
- Destruction of landscape for open cutting
- Carbon dioxide waste contributes to greenhouse affect
- Sulfur dioxide contributes to acid rain
