AOS 2-How can the versatility of non-metals be explained? Flashcards
what is a molecule?
it is a group of two or more atoms covalently bonded
how does something conduct electricity?
for something to conduct electricity, there must be free moving delocalised electrons
what does it mean if something is unable to conduct electricity?
if something is unable to conduct electricity, this means that there are no free moving electrons
what does it mean if something is able to conduct electricity?
if something is able to conduct electricity, this means that there are freely moving charged particles
what is an elements melting point?
an elements melting point is the amount of energy needed to break the intermolecular bonds
what is an elements boiling point?
an elements boiling point if the amount of energy needed to further break intermolecular bonds as well as the intramolecular bonds
what is intramolecular bond?
this bond is the bond present between atoms of a molecule
what is intermolecular bond?
this bond is the bond present between molecules
what does a high melting point indicate?
high melting point indicates strong intermolecular forces
what does a low melting point indicate?
low melting point indicates weak intermolecular forces
give 2 examples of non-metal elements(you can refer to a periodic table)
fluorine and chlorine
explain why non-metals do not conduct electricity
non-metals do not give away their electrons, so they do not have free flowing charged particles
explain why non-metals have low melting and boiling points
the bonds between these molecules are weak and so not much energy is required to break these bonds
what are the two most important types of bonds relating to molecular compounds
intermolecular and intramolecular
compare and contrast intermolecular and intramolecular bonds
-intramolecular bonds are much stronger than intermolecular bonds
what is covalent bonding?
covalent bonding is a type of bonding between non-metals. electrons are shared
where does covalent bonding occur?
it occurs between non-metals
how does covalent bonding happen?
it happens when two or more non-metals need electrons to fulfil their outer shells
how does covalent bonding differ to ionic bonding?
in covalent bonding, electrons are shared instead of being transferred like in ionic bonding
what is the octet rule?
it is a rule where an atoms valence shell must contain 8 electrons to be stable
what is a lone pair?
a lone pair is a pair of two electrons of an atom being bonded, but these electrons aren’t part of a bond
how can bonds between atoms be shown in a visual manner?
they can be shown in diagrams such as the lewis dot diagram/electron dot diagram and valence structure
what is electron dot structure?
electron dot structure is when the number of valence electrons are drawn around the elements symbol
what is valence structure?
it is when lines are drawn between chemical symbols to show each bond. one line will show 2 bonding electrons, 2 lines will show 4 bonding electrons. there is a maximum of 3 lines
in what atom/element might single bonds occur?
hydrogen
in what atom/element might double bonds occur?
oxygen
in what atom/element might triple bonds occur?
nitrogen
when are molecules most stable?
molecules are most stable when atoms have a full outer shell
what does VSEPR stand for?
valence shell electron pair repulsion
explain VSEPR theory
this theory models the idea that electron pairs in a valence shell will have a charge that will repel the other electron.
what are the 4 shapes of molecules?
- linear
- angular/bent v shape
- pyramidal
- tetrahedral
what are the three types of intermolecular forces?
dipole-dipole force, hydrogen bonding, dispersion force
how can the three types of intermolecular forces be explained?
the three types of intermolecular forces can be explained through electronegativity and polarity
what is electronegativity? what is the trend of this in the periodic table?
electronegativity is the tendency of an atom to attract electrons. this will increase up and left to right on the periodic table
what is polarity?
the tendency of a molecule to have an electric dipole
what is an electric dipole?
it is a slightly positive charge at one end of a molecule and a slightly negative charge on the other end.
what is a diatomic molecule?
it is a molecule made up of two atoms only, these atoms can be the same or different elements
what is a non-polar diatomic molecule? give an example
oxygen gas, O2
what is a polar diatomic molecule? give example
hydrogen fluorine, HF
what is dipole-dipole force?
a force that only occurs in polar molecules.
what is hydrogen bonding?
it is a special type of dipole dipole bond. it is when a hydrogen is bonded to a nitrogen, oxygen or fluorine atom
what are dispersion forces?
this force is present between all molecules. they result from random movement of electrons forming temporary dipoles
when do the three types of intermolecular forces occur?
dipole-dipole: occurs in polar molecules
hydrogen: occurs when a hydrogen atom is bonded to either fluorine, oxygen or nitrogen
dispersion: a force that is present in all molecules
order the three forces from strongest to weakest
hydrogen bonding, dipole-dipole, dispersion
why is carbon so important?
carbon is vital for life and the economy.
what are the isotopes of carbon?
carbon-12, carbon-13, carbon-14
is the melting point of carbon low or high?
the melting point of carbon is high
what sort of state change does carbon undergo?
carbon undergoes sublimation, where it changes state between solid and gas. it skips liquid
can carbon conduct electricity? explain
despite carbon being a non-metal, some structures/arrangements of carbon can allow it to conduct electricity.
what is an allotrope?
allotropes are different structural arrangements of the same element
what are the three allotropes of carbon?
diamond, graphite, amorphous carbon
describe properties of diamond
very hard because it has a 3D covalent lattice structure and each carbon is bonded to another carbon. diamond cannot conduct electricity
describe properties of amorphous carbon
carbon atoms are randomly arranged. it is a fine black powder which can conduct electricity.
describe properties of graphite
it is soft, its structure is a 2D layer lattice. conducts electricity because each carbon is bonded rot three other carbons and so there is one free moving electron.
why can carbon form so many compounds?
carbon always wants 4 bonds so this is why Caron can form many compounds
what are fullerenes?
they are spherical structures, with carbon atoms forming 3 bonds with delocalised electrons
how many bonds do carbon in fullerenes have?
3 bonds
what is the structure of fullerenes?
fullerenes are like a sphere.
what is graphene?
graphene is a single layer of graphite. it is 2D and each carbon is bonded to 3 other carbons
what are carbon nanotubes?
it is a layer of graphene rolled into a tube or cylinder
