Chemical Bonding Flashcards
what is chemical bonding?
attraction between atoms involving electron transfer/sharing to form new compounds
what is a grouped ion?
more than one atom involved in the ion
what is the symbol for carbonate and its charge?
symbol = CO3
charge = 2-
what is the symbol for ammonium and its charge?
symbol = NH4
charge = 1+
what is the symbol and charge for hydroxide?
symbol = OH
charge = 1-
what is the symbol and charge for nitrate?
symbol = NO3
charge = 1-
what is the symbol and charge for sulfate?
symbol = SO4
charge = 2-
what is the symbol and charge for phosphate?
symbol = PO4
charge = 3-
what is valency?
the number of electrons an atom needs to complete the outer shell
those electrons are either gained or lost
do non-metals gain or lose electrons?
gain
what is an ion
a charged particle (positive or negative)
how does the cross rule work?
are metals negatively or positively charged and why?
positively charged (cations)
they lose electrons
are non-metals negatively or positively charged and why?
negatibely charged (anions)
they gain electrons
in the centre of the atom are two sub-atomic particles
these particles are the …… and the …..
the ….. are positively charges
the ……have no charge and are …..
in the centre of the atom are two sub-atomic particles
these particles are the protons and the neutrons
the protons are positively charged
the **neutrons **have no charge and are neutral
the centre of an atom is ….. charged
the centre of an atom is positively charged
around the centre of the atom are negatively charges sub-atomic particles called …..
around the centre of the atom are negatively charges sub-atomic particles called electrons
the overall charge on an atom is ….
the number of …… and …… are equal
the overall charge on an atom is zero
the number of **protons and electrons **are equal
electrons are arranged in energy …. around the centre of the atom
the first energy …. is nearest to the centre and can take a maximum of …. electrons
the second and thur energy …. can take a maximum if …. electrons each
electrons are arranged in energy **shells **around the centre of the atom
the first energy shell is nearest to the centre and can take a maximum of 2 electrons
the second and thur energy shells can take a maximum if 8 electrons each
when atoms bond with other atoms, the number of electrons in their outermost energy shell ……
when atoms bond with other atoms, the number of electrons in their outermost energy shell changes
what are elements
substances that can’t be split into anything more simply by chemical means
what do all atoms in elements share?
the same atomic number
how are elements recognised in diagram?
the atoms have the same size or colour
what are compounds?
a combination of two or more elements in fixed proportions, joined together by strong bonds
does it matter if the compound is molecular, giant covalent or giant ionic?
no
what is a mixture?
the various components can be in any proportions
is an alloy a mixture? why?
yes because of the totally variable proportions
what is the differences in proportions between mixtures and compounds
A compounds proportions never vary
In a mixture the portions vary
If you wanted to mix some silvery zinc metal with some yellow sulphur, you could use any proportions
in zinc sulphide the proportions of zinc and sulphur have to be the exact same
what is the differences in properties between mixtures and compounds
in elements, each element has its own properties, but the properties of the compound are different
a mixture of hydrogen and oxygen would explode when you put it in a flame
a compound of hydrogen and oxygen to make water would put out a flame
what is the differences in ease of separation between mixtures and compounds
mixture can be separated by physical means
e.g. change in temperature, or dissolving part of the mixture in a solvent like water, things that do not involve chemical reactions
compounds have to be separated by chemical reactions
e.g. electrolysis
what is the differences in energy change between mixtures and compounds
there is little to no energy changes when making a mixture
there is greater energy changes when making a compound
explain why hydrogen is gas at room temperature
hydrogen is a simple molecule and so has weak intermolecular forces between its molecules
these weak forces break at room temperature
hydrogen chloride has a …… molecular structure
there are …. forces between the ….
because of this, hydrogen chloride has a ….. boiling point
hydrogen chloride has a simple molecular structure
there are weak forces between the molecules
because of this, hydrogen chloride has a low boiling point
why is pure copper malleable?
pure metals are malleable because of their same sized atoms and arrangement
layers can easily slide over each other because in metals there are delocalised electrons which allow copper ions to do this
bronze is a mixture of tin and copper, the tin atoms are much bigger than the copper atoms
why is bronze not as malleable as copper
the different size of atoms (tin is much bigger than copper) mean that they can’t slide over each other
why do metals conduct electricity?
delocalised electrons fall between the layer of atoms and conduct electricity
a substance has:
melting point = 540C
boiling point = 1200C
electrical conductivity as solid = poor
electrical conductivity as liquid = poor
electrical conductivity as aqueos solution = poor
what type of structure is it?
covalent: simple
a substance has:
melting point = 4030C
boiling point = 5670C
electrical conductivity as solid = good
electrical conductivity as liquid = good
electrical conductivity as aqueos solution = not soluble
what type of structure is it?
metallic
a substance has:
melting point = -2100C
boiling point = -1960C
electrical conductivity as solid = poor
electrical conductivity as liquid = poor
electrical conductivity as aqueos solution = poor
what type of structure is it?
covalent: simple
CHECK
a substance has:
melting point = 16100C
boiling point = 22300C
electrical conductivity as solid = poor
electrical conductivity as liquid = poor
electrical conductivity as aqueos solution = not soluble
what type of structure is it?
covalent: giant
a substance has:
melting point = 6150C
boiling point = 8760C
electrical conductivity as solid = poor
electrical conductivity as liquid = good
electrical conductivity as aqueos solution = good
what type of structure is it?
ionic
a substance has:
melting point = 37270C
boiling point = 48270C
electrical conductivity as solid = good
electrical conductivity as liquid = good
electrical conductivity as aqueos solution = not soluble
what type of structure is it?
metallic
a substance has:
melting point = 560C
boiling point = 3420C
electrical conductivity as solid = good
electrical conductivity as liquid = good
electrical conductivity as aqueos solution = good
what type of structure is it?
metallic
a substance has:
melting point = 9340C
boiling point = 15680C
electrical conductivity as solid = poor
electrical conductivity as liquid = good
electrical conductivity as aqueos solution = insoluble
what type of structure is it?
ionic
a substance has:
melting point = -1050C
boiling point = -450C
electrical conductivity as solid = poor
electrical conductivity as liquid = poor
electrical conductivity as aqueos solution = good
what type of structure is it?
covalent: simple
CHECK
state whether you would expect calcium flouride (ionic bonding) to have a high or low melting point and why
high
stronger attraction between the positive Cl atoms and negative F atoms
lots of energy needed
what is the chemical formula for Calcium Flouride
CaF2
what is the chemical formula for Potassium Bromide
KBr
what is the chemical formula for Barium NItrate
Ba(NO3)2
what is the chemical formula for Beryllium Oxide
BeO
what is the chemical formula for magnesium phosphate
Mg3(PO4)2
what does the ‘(II)’ in Copper (II) indicate?
each copper atom contributes 2 electrons
why can copper conduct electricity?
because it has a sea of delocalised electronsnbetween the layers in the structure which are free to move
why can copper be drawn into wires
copper is ductile
the sea of delocalise delectrons mean the layers can slide easily over each other and be drawn into wires
what is a use for poly(ethene)
wax in polish
why does propanone and water (both simple molecular structures) have low boiling points
the attractive forces between their molecules are weak
these require little energy to be overcome
ammonia is:
ionic bonding / covalent bonding
insoluble in water / soluble in water
covalent bonding
soluble in water
methane is:
ionic bonding / covalent bonding
insoluble in water / soluble in water
covalent bonding
insoluble in water
poly(ethene) is:
ionic bonding / covalent bonding
insoluble in water / soluble in water
covalent bonding
insoluble in water
sodium chloride is:
ionic bonding / covalent bonding
insoluble in water / soluble in water
check
sodium hydroxide is:
ionic bonding / covalent bonding
insoluble in water / soluble in water
ionic bonding
soluble in water
give two observations made during the reaction between magnesium and oxygen
a huge bright light is seen
a sizzle is heard whilst the reaction occurs
why is the melting point of magnesium oxide much higher than that of sodium chloride?
lattice is held together by stronger attraction
this is because the ions have a higher charge and therefore a higher attraction
Suggest and explain why silica is used to make bricks for high-temperature furnaces. In your answer, you should refer to the structure of, and bonding im, silica
giant covalent stucture
strong covalent bonds between atoms
lots of energy to breka bonds - makes them suitable to withdstand heat
When glue sets it forms a giant covalent structure
explain why the giant covalent structures have high melting points?
they have strong covalent bonds which take a lot of energy to break so it needs to be a high heat to break these bonds
