C2.2 Bonding Flashcards
Metal properties
- Shiny
- usually high mpt & bpt
- solid @ room temp
- malleable - bend without shattering
- ductile - can be pulled into wires
- good thermal and electrical conductors
- metals lose electrons to form positive ions
- metals don’t react together, instead they mix to form alloys
- if dissolved in water metal oxides produce alkaline solutions
Non - metal properties
- dull
- usually low mpt & bpt
- approx half solid & half gas a@ room temp
- brittle - shatter when hammered
- non-ductile - snap when pulled
- poor conductors - they are insulators
- non-metals gain electrons to form negative ions
- non-metals react with each other to produce compounds that consist of molecules
- if dissolved in water non-metal oxides produce acidic solutions
periodic table periods
go horizontal, as you go along the atomic number of each element increases by 1 . TMT number of electrons in each atom also increases by 1 each time
periodic table groups
elements of the same group have similar properties. This is due to the arrangement of their electrons.
group 1
- alkali metals
- low density
- react vigorously with water
- soft metals, easily cut - shiny when cut
- reactivity increases down the group
- low mpt + bpt
group 2
produce weakly alkaline solutions when they react with water
group 7
Halogens - non-metals - many similar chem properties
- salts of halogens (AKA halides) commonly found in sea water
- reactivity decreases down the group
- mpt, bpt, density, colour intensity increases down the group
- 7 electrons in outer shell
group 0
noble gases - inert / unreactive gases
- colourless
- very stable
- full outer shell
transition metals
- shiny hard metals - except mercury (liquid at room temp)
- usually produce brightly coloured compounds
how are elements arranged in the periodic table?
increasing atomic number across periods
similar reacting elements arranged in groups
what is an alloy?
a mixture of two or more metal elements - e.g. steel, brass
what is the mass number?
number of protons + neutrons (normally top number / bigger number)
what is the atomic number?
number of protons (or electrons) in the atom (normally bottom number / lower number)
which electron shell has the lowest energy level?
the shell closest to the nucleus
what is an ion?
charged particle
what ions does ionic bonding occur between?
metals and non-metals
characteristics of ionic compounds - hhuudd
- high mpt
- hard but brittle
- uniform structure
- unreactive when solid
- dissolve in water to create solutions
- don’t conduct elec when solid, but do in solution / molten
what do covalent bonds form between?
non-metal atoms - share electrons between atoms
what are simple molecular substances
solids, liquids or gases with low mpt & bpt
simple covalent bond properties (simple molecular substances
- low mpt & bpt - weak intermolecular forces, break down easily
- non-conductive - no free electrons/overall electric charge
- soft and brittle - insoluble in water, soluble in other substance e.g. petrol
- can be v. reactive - due to size + combination of non-metals
covalently bonded molecules all have….
v. strong bonds between atoms in molecules - weaker forces between molecules holding them together
- when covalent structure melts/boils, weak intermol forces break NOT strong covalent bonds
what are giant covalent structures also refered to as?
macromolecules
what produces giant covalent structures NOT molecules
millions of atoms joining together
how are giant covalent structures usually arranged?
in giant regular lattices
properties of giant covalent structures
- v. strong structures - many bonds
- bonds are all covalent - v. high mpt + bpt
- hard but brittle
name to allotropes of carbon
diamond and graphite
what is an allotrope?
2 or more diff physical forms in which an element can exist
what is graphene?
one sheet of graphite
what is diamond made up of?
its a form of carbon where each carbon atom is joined to four other carbon atoms forming a giant covalent structure
diamond properties
- v. hard
- high mpt
- doesn’t conduct electricity - no free electrons
- hardest naturally occurring substance on earth
what is graphite made up of?
form of carbon where carbon atoms for layers - slide over each other - graphite much softer than diamond
- carbon atoms each joined to 3 other carbon atoms - strong bonds - makes hexagonal sheets of atoms
- forms rings of 6 atoms - many layers - strong bonds in hexagons but weak bonds between layers
why does graphite conduct electricity?
- free electron from each C atom can move in between layers
why can the layers of graphite slide over each other easily?
as bonds between layers are weak
graphite properties
- v. high mpt - break strong covalent bonds
- soft - layers
- conduct electricity
what is a fullerene
pure carbon molecule composed of at least 60 carbon atoms
what is Buckminsterfullerene
allotrope of carbon
- giant molecule NOT giant covalent structure
- carbon bonds to 3 other C atoms - 1 double bond, 2 single bonds - atoms arranged in 12 pentagons + 20 hexagons - forms ‘Bucky balls’
what can fullerenes join together to form?
nanotubes - v. strong but light structures
what is metallic bonding between?
only between metal atoms
what is metallic bonding?
force of attraction between free delocalised electrons and the metal ions - strong so can keep regular structure, usually have high mpt + bpt
are metals malleable?
yes - delocalised electrons allow metal atoms to slide past each other without being subjected to strong repulsive forces
what is an alloy?
a mixture of 2 or more elements - at least one is a metal
what is a nanoparticle?
1-100nm - usually contain a few hundred atoms - abt 100x bigger than atoms and simple molecules
what are polymers typically bonded by?
covalent bonds
thermosoftening polymers
can be hated to soften them then remoulded into new shape that sets when they cool down
- these polymer chains are relatively easy to break
thermosetting polymers
cant be remoulded, instead they char or burn when heated
- these polymer chains normally joined by strong covalent bonds, cross-linking
