Atoms and Elements Ch 1-4 Pearson Flashcards
materials (d)
substances used to make objects.
2 types of materials are
pure substances (elements and compounds) or mixtures
Materials with distinct and measurable properties like melting points or density
pure substances
Materials that have variable properties depending on the relative amounts of substances present
mixture
Melting point and boiling point, density, hardness are all ________ properties.
physical
Two types of pure substances
elements and compounds
Compound
two or more elements chemically combined
Chemical formula
shows the elements present in a compound and the ratio between them
Separation techniques use __________ properties of substances to separate them
physical
Separation techniques use these physical properties
5
particle size, solubility, density, magnetism and boiling point
Nanoparticles
particles that are 1-100 nm in diameter.
Nanometre
1 x 10 -9 metres
Is wood a material? Why?
Yes. It is used to make other objects like houses.
Is carbon dioxide a material? Why?
No. No objects are made of carbon dioxide.
Elements
sustance made up of one type of atom.
Atoms are the same type if they have the same number of protons. Neutrons and electrons may differ.
Atom 1 has 6 protons and 6 neutrons.
Atom 2 has 6 protons and 7 neutrons.
Are they the same type of atom?
Yes. They have the same number of protons
Atom 1 has 6 protons and 6 neutrons
Atom 2 has 5 protons and 6 neutrons.
Are they the same type of atom?
No. They have different number of protons.
Can you change the melting point of an element?
No
Can you change the melting point of a compound?
No
Can you change the melting point of a mixture
Yes -change the ratio of components
Metal
a substance with high electrical and thermal conductivity and lustre ( reflects light when freshly prepared). Also ususally malleable and ductile
Metals found pure on Earth
gold, silver copper
alloy
a mixture of a metal and other metals or carbon
Steel is an alloy of what two main elements?
iron and carbon
polymer
a substance made up of repeating smaller units bonded together
Polymers may be natural or man made. Classify the following as natural or man made.
WOOL PLASTIC RUBBER NYLON SILK POLYSTYRENE
In order:
N MM N MM N MM
Ceramic
Inorganic, non-metal solid. Made from firing clay
Bonds in ceramics
ionic and covalent
Properties of ceramics
hard and brittle. Can withstand high temps. Most good insulators - some semi or superconductors.
What is nanotechnology?
study of materials on the nanoscale. 10 x -9
How large is a nanometre?
a billionth of a metre
How big are nanoparticles
Diameter of 1 - 100 nm
Why can nanoparticle be useful or harmful to humans?
Can pass through air, skin and cells
Separation techniques use ________ and ________ properties to separate a mixture of substances
physical and chemical