C2.2 Flashcards
Physical Property | Metal elements | non-metal elements
Apperance | shiny | dull
Melting/boiling point | usually high | usually low
State at room temp. | solid | around half gas, half solid
Malleable (can be bent) when solid | yes | no
Ductile (can be pulled) when solid | yes | no
Conductor or insulator | conductor | insulator
Metals form ___ ions
Positive
They lose electrons
Metals, non-metals, and reactivity
Metals don’t react with each other, instead they mix to form alloys
Non-metals can react with each other, and form compounds via covalent bonding
Ionic compounds
Contain positive and negative ions
Ions are arranged regularly, known as a giant ionic lattice
Ions are held in place by electrostatic forces
Simple molecule
A molecule that only contains a few atoms
Electrostatic forces are between the nucleus and the shared electron, not between whole charged atoms
Weak intermolecular forces
Giant covalent structure
A structure formed by very many non-metal atoms joined together via covalent bonds
Polymer
A substance made up of smaller pieces known as monomers
Polymers -
Thermosoftening | Thermosetting
Can be heated to soften them, then be remoulded |
Cannot be remoulded, will burn when heated
No cross linking | has cross linking (covalent bonds between chains)
Repeating unit
A section of a polymer that is repeated
Metallic bonds
Bonds within metals between the metal ions and delocalised electrons
Developing the periodic table
Dalton - tried creating a system to symbolise elements, his original list had 5 elements (hydrogen, oxygen, nitrogen, carbon, and sulphur)
Newland - published his law of octaves, arranged all known elements into a table in order of relative atomic mass, table showed repeating patterns of properties, out iron with oxygen and sulphur (non-metals)
Mendeleev - arranged elements with similar properties into vertical columns, and in order of relative atomic mass. Left spaces for undiscovered elements
Moseley - proved that every elements identity was determined by the number of protons it had, allowed him to predict 4 new elements that were later discovered
Group 1
Type of element - metal
Reactivity - very reactive
Electron structures - ends in 1
Ion - +1
Group 2
Type of element - metal
Reactivity - reactive
Electron structure - Ends in 2
Ion formed - +2
Group 7
Type of element - non-metal
Reactivity - very reactive
Electron structures - Ends in 7
Ion formed: -1
Group 0
Type of element - non-metal
Reactivity - unreactive
Electrons structure - full outer shell
Ion formed - doesn’t form an ion
Allotrope
A different form of an element, in the same state, but with different atomic arrangements
Diamond (carbon allotrope)
Giant covalent structure
Each carbon atom is bonded to 4 other carbon atoms
No delocalised electrons, so can’t conduct
Transparent, durable, hard
High melting point, used in jewellery and drills
Graphite
Giant covalent structure
Each carbon atom is bonded to 3 other carbon atoms
Has delocalised electrons, can conduct
Soft, oqaue
High melting point, used in pencil tips and as a dry lubricant
Graphene
One atom thick
Almost transparent
Very strong and conducts electricity
Can be used in flexible touch screens and solar cells
Buckyball
Carbon atoms form pentagons and hexagons
Can be used as a lubricant, and deliver medicinal drugs straight to cells in the future
Metals are malleable because…
Layers of metal ions can slide over each other
Nanoparticles
A particle between 1nm and 100nm in diameter
Benefits of nanoparticles
Different properties to the same substance in bulk, e.g titanium dioxide is transparent as a nanoparticle making it useful in sunscreen and cosmetics
They have a very large surface area to volume ratio, so they are capable of being used at catalysts for industrial chemical reactions
Disadvantages of nanoparticles
So tiny they can be breathed in, absorbed by the skin, or pass into cells
May be harmful to our health and the environment in ways that are difficult to predict
