Atomic Structure and the Periodic Table Year 10 Flashcards
describe the trend in reactivity in group 1 elements as you go down the group
increasing reactivity, lower melting and boiling points, higher relative atomic mass
state the word equation for the reaction of water and a group 1 metal (sodium)
sodium + water -> sodium hydroxide + hydrogen
state the word equation for the reaction of chlorine and a group 1 metal (sodium)
sodium + chlorine => sodium chloride
state the ionic equation for the reaction for the electrolysis of lead bromide at the anode and the cathode
anode :
Pb2+ + 2e- –> Pb
cathode:
2Br- –> Br2 + 2e-
why can ionic solids only be extracted in molten state?
- when solid, ions are in a fixed position and cant move.
- in a liquid state the ions can move around freely to conduct electricity (needed for electrolysis)
name the ore aluminium is found naturally in and what compound is contained in it
bauxite
al2o3
give a disadvantage of extracting metals from their ore
it is very expensive as lots of energy is needed to melt the ore
why is cryolite added to bauxite when extracting aluminium
- contains Al2O3 which has a v. high melting point.
- lowers the melting point, reducing the amount of energy needed to melt bauxite, reducing the cost of the process
describe the electrolysis of aluminium from its ore
- the molten mixture contains free ions so conducts electricity
- cathode attracts positive al+3 ions
- they gain 3 electrons (reduced) and form neutral al atoms which sink to the bottom of the tank
- anode attracts negative o2- ions
- they lose 2 electrons (oxidised) making neutral oxygen atoms forming o2 molecules
state the ionic equation for aluminium extraction at the cathode
Al3+ + 3e- –> Al
state the ionic equation for aluminium extraction at the anode
2O2- –> O2 + 4e-
state the ionic equation for aluminium extraction
2AL2O3 –> 3O2 + 4AL
define reduction in terms of electrons and oxygen
reduction is a gain of electrons and a loss of oxygen
define oxidation in terms of electrons and oxygen
oxidation is a loss of electrons and a gain of oxygen
define a redox reaction
a reaction where reduction and oxidation happens at the same time
give an example of a redox reaction (general word equation)
acid + metal –> salt + hydrogen
recall the reactivity series
potassium sodium lithium calcium magnesium aluminium zinc iron copper silver gold
how do you measure reactivity (method)
- measure temp change of the reaction between the acid/water and metal over a set period of time.
- the more reactive the metal, the higher the temp change
state the general word equation for the reaction between metal and water
metal + water –> metal hydroxide + hydrogen
state the general word equation for the reaction between group 1 metals and water (where X represents the metal)
2X + 2H2O –> 2XOH + H2
state the general word equation for the reaction between group 2 metals and water (where X represents the metal)
X + 2H2O –> X(OH)2 + H2
why is the relative atomic mass of chlorine a decimal?
- chlorine exists as different isotopes (different numbers of neutrons) so the ar is an average.
- takes into account the diff. masses and amounts of the isotopes that make up the element
what is the avragado constant?
6.02 x 10 to the power of 23 particles
state the formula to work out moles
moles = mass / mr
state the relationship between the amount of product formed and the limiting reactant
amount of product formed is directly proportionate to the limiting reactant (if you half the l.r the product halves)
state the formula to work out % mass
% mass = (ar x no. of atoms)/mr x100
state the formula to work out concentration of a solution. give units
conc. = mass / volume
g/dm3) (g) (dm3
state the methods for separating metals from metal oxides in terms of carbon and their reactivity
- electrolysis for metals higher than carbon
- ‘reduction using carbon’ for metals lower than carbon (as carbon can only take in oxygen from metals less reactive than itself)
state general word equation for the reaction btwn an acid and metal and describe what happens in terms of electrons and reactivity
acid + metal –> salt + hydrogen
- metal ion loses electrons forming positive ion
- the higher the reactivity of the metal the more easily it reacts
this is carbon:
12
C
6
what does the bigger and smaller number tell you about carbon
- bigger number is mass number. how many protons and neutrons (12 in total)
- smaller number is atomic number. tells you how many protons in the atom. protons are equal to number of electrons. 6 electrons and 6 protons
number of neturons = 12-6 = 6
chemical formula for ammonia
NH3
chemical formula for sulfuric acid
H2SO4
nitrogen and hydrogen gas react together to form ammonia, write the balanced sybmol for this
N2+H2 ==> NH3
N2 + 3H2 ==> 2NH3
name the 4 ways you can separte mixtures
distillation
fractional distillation
filtration
evaporation
what does the group number and the period number tell you about an element
- group number (columns) tells you how many electrons are in the outer shell of the element
- period number (rows) tell you how many shells are occupied
give the electronic structure of magnesium
2,8,2
what is an ion
an atom that has lost or gained electrons
give the formula for a lithium ion
Li+
give the formula for a magnesium ion
Mg2+
give the formula for an aluminium ion
Al3+
give the formula for a nitrate ion
NO3-
give the formula for a potassium ion
K+
give the formula for a
chloride ion
Cl-
give the formula for a nitride ion
N3-
give the formula for a silver ion
Ag+
give the formula for a iron(II) ion
Fe2+
give the formula for a iodide ion
I-
give the formula for a copper (II) ion
Cu+
give the formula for a calcium ion
Ca2+
give the formula for a lead (II) ion
Pb2+
give the formula for a bromide ion
Br-
give the formula for a sodium ion
Na+
give the formula for a zinc ion
Zn2+
give the formula for a flouride ion
F-
give the formula for a oxide ion
O2-
give the formula for a hydrogen ion
H+
give the formula for an ammonium ion
NH4+
give the formula for a barium ion
Ba2+
give the formula for a copper (II) ion
Cu2+
give the formula for an iron (III) ion
Fe3+
give the formula for an aluminium ion
Al3+
give the formula for a hydroxide ion
OH-
give the formula for a nitrate ion
NO3-
give the formula for a sulfide ion
S2-
give the formula for a sulfate ion
SO4^2-
give the formula for a carbonate ion
CO3^2-
what is a compound
2 or more elements chemically bonded together in equal proportions
what is a mixture
can be emements or compounds
may or may not be chemically bonded together