SC4-6 Flashcards
how did mendeleev group his periodic table
increasing atomic masses and similar properties
how is the modern periodic table grouped
by increasing atomic number and elements with similar properties are in the same group
what are ionic bonds and what are they between
between metals and non metals where electrostatic forces hold oppositely charged ions together
how does an atom become an ion and what kind of ions do metals and non metals become
it loses / gains an electron
metals become cations
non metals become anions
what can make an atom stable
having a full outer shell of electrons
ionic compound properties and what does it form
high mp and bp
conducts electricity - when not solid
forms crystals
describe an ionic lattice
billions of ions packed in a regular repeating arrangement
for a substance to conduct electricity it must have…
charged, free moving particles
name the positive and negative electrode
positive electrode - anode
negative electrode - cathode
what are cations and anions attracted to
cations - cathode
anions - anode
what are covalent bonds between and how are they formed
non metals by sharing pairs of electrons
molecular compound properties
low mp and bp
cant conduct electricity
define a polymer and monomer
give an example for both
polymer - chain of monomers
monomer - small simple molecules
polyethene (polymer) made of ethene (monomers)
how does the length of a polymer affect its mp and bp
longer polymers have higher mp and bp
define an allotrope
different structural forms of the same element
what forms fullerene
and an example of a fullerene
carbon
example: buckminsterfullerene
fullerene properties
low mp
simple molecule
weak IM forces
soft/ slippery
molecules strong due to covalent bonds
graphene properties
lightest known material
not a simple molecule
good electrical conductor
sheet of carbon atoms with no fixed formula
molecules strong due to covalent bonds
difference between graphene and fullerene
graphene is not a simple molecule whilst fullerene is
two examples of giant structures of carbon
diamond and graphite
giant structures of carbon properties
high mp
3D
networks of carbon linked by covalent bonds
number of covalent bonds for each carbon atom graphite has
3
number of covalent bonds for each carbon atom diamond has
4
what is graphite used for and why
electrodes in electrolysis because its unreactive and cheap
