The periodic table Flashcards
the number of protons in an atom is the same as the…
number of electrons and is called the atomic number
what is the name for the configuration and distance that the electrons are away from the nucleus
electronic configuration
and shells
are elements on the periodic table listed in order of increasing or decreasing atomic numbers
increasing
what are the horizontal rows called on the periodic table
periods
what are the vertical rows called on the periodic table
groups
what is the group number the same as
the number of electrons in the outermost shell
elements in the same group have similar what
chemical properties, because they have the same number of electrons on their outer shell
what is group 1 called
alkali metals
why is group 1 called alkali metals
because they all react with water to form alkaline solutions
what is group 7 called
halogens
why is group 7 called halogens
it means ‘salt maker’, halogens form salts when they react with metals
why is group 7 called halogens
it means ‘salt maker’, halogens form salts when they react with metals
what is group 8/0 called
noble gases
why is group 8/0 called noble gases
because they are unreactive (full outer shell)
how does the periodic table change from left to right
gradually from metal to non metal
what is another word for a semi-metal
a metalloid (it has some metal properties but isn’t actually a metal)
6 metals of group 1
lithium sodium potassium rubidium caesium francium (radioactive and little know about its properties)
lithium sodium and potassium physical properties
- good conductors of electricity and of heat
- soft and can easily be cut with a knife
- low melting and boiling points compared with more typical metals
- low densities (all float on water)
- stored in oil at schools
lithium sodium and potassium chemical properties
- shiny surfaces when freshly cut, but quickly tarnishes as it reacts with oxygen in the air
- all burn in air or oxygen to form white and solid oxides:
2M + O2 –> M2O
M= one of the three metals - they react vigorously with water to give an alkaline solution of the metal hydroxide as well as hydrogen gas :
2M + 2H2O –> 2MOH + H2
observations when lithium is added to water
- moves around the surface of the water
- hissing sound
- bubble of gas
- gets smaller and smaller –> eventually disappears
observations when lithium is added to water
- moves around the surface of the water
- hissing sound
- bubble of gas
- gets smaller and smaller –> eventually disappears
observations when sodium is added to water
- moves around the surface of the water
- hissing sound
- bubble of gas
- gets smaller and smaller –> eventually disappears
- melts into a shiny ball
observations when potassium is added to water
- moves around the surface of the water
- hissing sound
- bubble of gas
- gets smaller and smaller –> eventually disappears
- melts into a shiny ball
- burns with a lilac coloured flame
the further you go down group 1 what should we observe
more reactive metals
the further down group 1 less energy is needed to overcome the electrostatic forces of attraction with the ext a outside electron therefore
- francium is the most reactive out of group 1
- the size of the atom increases and therefore the outer electron gets further away from the nucleus
- the outer electron is therefore less strongly attracted to the nucleus
the further down group 1 less energy is needed to overcome the electrostatic forces of attraction with the ext a outside electron therefore
- francium is the most reactive out of group 1
- the size of the atom increases and therefore the outer electron gets further away from the nucleus
- the outer electron is therefore less strongly attracted to the nucleus
3 most common metals from the halogens
chlorine, bromine and iodine (all non metals and poisonous)
state at room temp and colour: chlorine
gas
pale green
state at room temp and colour: bromine
liquid
red-brown (readily evaporates to form a brown gas)
state at room temp and colour: iodine
solid
black (but sublimes when heated to form a purple gas)
how do the three main elements from the halogens react with iron similarly:
hot iron wool glows brightly when chlorine passes over it. brown smoke forms and a brown solid is left behind.
how do the three main elements from the halogens react with iron similarly:
Chlorine: hot iron wool glows brightly when chlorine passes over it. brown smoke forms and a brown solid is left behind.
Bromine: hot iron wool glows less brightly when bromine vapour passes over it. brown smoke forms and a brown solid is formed.
Iodine: hot iron wool glows even less brightly when iodine vapour passes over it. brown smoke forms and a brown solid is formed.
how do the three main elements from the halogens react with iron similarly:
Chlorine: hot iron wool glows brightly when chlorine passes over it. brown smoke forms and a brown solid is left behind.
Bromine: hot iron wool glows less brightly when bromine vapour passes over it. brown smoke forms and a brown solid is formed.
Iodine: hot iron wool glows even less brightly when iodine vapour passes over it. brown smoke forms and a brown solid is formed.
what is the reactivity trend down the halogens
decreases down the group because of the increasing size of the atoms (attracting an extra atom less attraction of the other atom as there are more shells further away from the nucleus)
chlorine reaction with hydrogen
a mixture of hydrogen and chlorine explodes when exposed to UV radiation
H2 + Cl2 –> 2HCl
bromine reaction with hydrogen
a mixture of hydrogen and bromine vapour will react when heated
H2 + Br2 –> 2HBr
iodine reaction with hydrogen
a mixture of hydrogen and iodine vapour will react when heated, but the reaction does not go completion
H2 + I2 –> 2HI
an example of a displacement reaction where chlorine is more reactive than the aqueous solution
chlorine + potassium bromide solution –> potassium chloride solution + bromine
in general a halogen will displace a … reactive hydrogen for an aqueous solution solution of its halide
less
in general a halogen will displace a … reactive hydrogen for an aqueous solution solution of its halide
less
aqueous solutions of the halogen has the following colours: chlorine
very pale green, but usually appears colourless since it is often dilute
aqueous solutions of the halogen has the following colours: bromine
orange, turns yellow when diluted
aqueous solutions of the halogen has the following colours: iodine
brown
in displacement reaction, the halogen molecules is gaining electrons and is therefore being reduced. the ionic half equation for this reaction:
X2 + 2e- –> 2X-
the halide ions are losing electrons and are therefore being oxidised. redox reaction as both reduction and oxidation are taking place. the ionic half equation for this reaction:
2Y- –> Y2 + 2e-
HCl dissolved in methylbenzene and in water: effect on blue litmus
no change –> not acidic
turns red –> acidic
how to show that air contains approx. one fifth oxygen: using iron
- place wet iron filings in the end of a burette and set up the apparatus as shown in the diagram
- over several days the water will rise up the burette and reach a constant level
- this is because the iron reacts with the oxygen in the air
- take the initial and final reading of the water level in the burette
- the volume of air at the start = (50 - initial burette reading)
- the percentage of oxygen in air can be calculated using the equation:
percentage of oxygen = volume of oxygen used/volume of air at start x 100
how to show that air contains approx. one fifth oxygen: using phosphorus
- a similar experiment can be done like the one using iron, but with a piece of white phosphorus
- levels of water inside and outside the tube are equal
- levels equal; phosphorus touched by hot metal rod
- levels equal; phosphorus starts burning
- levels inside higher: phosphorus stops burning
4P(s) + 5O2(g) –> 2P2O5(s)
how to prepare oxygen in a lab
- hydrogen peroxide, H2O2, decomposes slowly to form water and oxygen
- The speed of the decomposition is increased by adding solid manganese dioxide MnO2, which acts as a catalyst for the reaction
- the oxygen can also be collected over water
- since oxygen is not very soluble in water, very little is lost
- an aqueous solution of hydrogen peroxide is used in the lab prep
2H2O(aq) –> 2H2O(l) + O2(g)
HCl dissolved in methylbenzene and in water: effect of electricity
does not conduct –> not contain ions
hydrogen evolved at the negative electrode
chlorine evolved at the positive electrode –> contains ions
HCl(aq) –> H+ (aq) + Cl- (aq)
typical properties of hydrochloric acid
- turns litmus paper red
- has a low pH and hence turns Universal indicator red
- reacts with fairly reactive metals i.e. magnesium, zinc, iron to form a metal chloride in solution and liberate hydrogen gas
typical properties of hydrochloric acid
- turns litmus paper red
- has a low pH and hence turns Universal indicator red
- reacts with fairly reactive metals i.e. magnesium, zinc, iron to form a metal chloride in solution and liberate hydrogen gas
- reacts with metal carbonates to form a metal chloride in solution, water and carbon dioxide gas
- reacts with bases (metal oxides and metal hydroxides) to form a metal chloride in solution and water
typical properties of hydrochloric acid
- turns litmus paper red
- has a low pH and hence turns Universal indicator red
- reacts with fairly reactive metals i.e. magnesium, zinc, iron to form a metal chloride in solution and liberate hydrogen gas
- reacts with metal carbonates to form a metal chloride in solution, water and carbon dioxide gas
- reacts with bases (metal oxides and metal hydroxides) to form a metal chloride in solution and water
both carbon dioxide and sulphur dioxide are … oxides. they dissolved in water to form acidic solutions, give the equations for these reactions:
acidic
CO2(g) + H2O(l) –> H2CO3(aq) = carbonic acid (approx pH 5-6)
SO2(g) + H2O(l) –> H2SO3(aq) = sulphurous acid (approx pH 3-4)
how to show that air contains approx. one fifth oxygen: using copper
- set up the apparatus with 100cm(cb) of air in one of the gas syringes
- heat the copper at one end of the silica tube using a blue Bunsen flame
- pass the air backwards and forwards over the copper
- as the volume of gas in the syringes decreases, move the Bunsen flame along the tube so that it is always heating fresh copper
- stop heating when the volume of gas in the syringes stops decreasing, the copper is reacting with the oxygen in the air to form black copper (II) oxide:
2Cu(s) + O2(g) –> 2CuO(s) - the final volume of air in the syringe will be approx. 79 cm(cb) showing that 21cm(cb) has reacted
how to show that air contains approx. one fifth oxygen: using iron
- place wet iron filings in the end of a burette and set up the apparatus as shown in the diagram
- over several days the water will rise up the burette and reach a constant level
- this is because the iron reacts with the oxygen in the air
- take the initial and final reading of the water level in the burette
how to prepare carbon dioxide in a lab
- the reaction between any metal carbonate and an acid will produce carbon dioxide
- calcium carbonate is the most commonly used metal carbonate in the lab prep for CO2
- the most convenient form of calcium carbonate to use is marble chips
- CaCO3(s) + 2HCl(aq) –> CaCl2(aq) + H2O(l) + CO2(g)
- carbon diode is not very soluble in water so it van be collected over water without much being lost, it can also be collected downward delivery in air as it is more dense than air
- carbon dioxide is also produced when most metal carbonates are heater
how to prepare oxygen in a lab
- hydrogen peroxide, H2O2, decomposes slowly to form water and oxygen
- The speed of the decomposition is increased by adding solid manganese dioxide MnO2, which acts as a catalyst for the reaction
- the oxygen can also be collected over water
- since oxygen is not very soluble in water, very little is lost
- an aqueous solution of hydrogen peroxide is used in the lab prep
2H2O(aq) –> 2H2O(l) + O2(g)
observation and equation: magnesium heated in oxygen
burns with a bright white flame to form a white powder
2Mg(s) + O2(g) –> 2MgO(s)
observation and equation: carbon heated in oxygen
burns with a yellow-orange flame to form a colourless gas
C(s) + O2(g) –> CO2(g)
observation and equation: sulphur heated in oxygen
burns with a blue flame to form a colourless gas
S(s) + O2(g) –> SO2(g)
magnesium oxide MgO, is a … oxide. it is very slightly … in water and a sat rated solution with have a pH of about … it reacts with water to form a solution of … Mg(OH)2: give this equation
basic soluble 10 magnesium hydroxide MgO(s) + H2O(l) --> Mg(OH)2(aq)
uses of carbon dioxide
- making fizzy/carbonated drinks –> CO2 not usually soluble in water at normal atmospheres but becomes soluble when put under pressure
- in fire extinguishers (prevents oxygen from getting to the flame), does not support combustion
oxides of metals are basic, if they dissolve in water they form what
alkaline solutions
oxides of non-metals are often … if they dissolve in water they form … solutions. some oxides of non-metals are neutral e.g. carbon monoxide
acidic
acidic
how to prepare carbon dioxide in a lab
- the reaction between any metal carbonate and an acid will produce carbon dioxide
- calcium carbonate is the most commonly used metal carbonate in the lab prep for CO2
- the most convenient form of calcium carbonate to use is marble chips
- CaCO3(s) + 2HCl(aq) –> CaCl2(aq) + H2O(l) + CO2(g)
thermal decomposition (breakdown by heating) observations and equation: copper (II) carbonate
green to black
CuCO3(s) –> CuO(s) + CO2(s)
thermal decomposition (breakdown by heating) observations and equation: magnesium carbonate
stays white
mgCO3(s) –> MgO(s) + CO2(g)
thermal decomposition (breakdown by heating) observations and equation: calcium carbonate
stays white
CaCO3(s) –> CaO(s) + CO2(g)
thermal decomposition (breakdown by heating) observations and equation: zinc carbonate
white to yellow when hot and white again when cold
ZnCO3(s) –> ZnO(s) + CO2(g)
thermal decomposition (breakdown by heating) observations and equation: sodium carbonate
stays white
doesn’t decompose in a Bunsen flame
uses of carbon dioxide
- making fizzy/carbonated drinks
- in fire extinguishers (prevents oxygen from getting to the flame)
metals … hydrogen in the reactivity series react with both dilute hydrochloric acid and dilute sulphuric ace to form a …
above
salt and hydrogen
metal + dilute hydrochloric acid –> ? + hydrogen
metal + dilute sulphuric acid –> ? + hydrogen
metal chloride
metal sulphate
observation of reaction with HCl or H2SO4 and equations: magnesium
- bubble of gas
- magnesium disappears
- reaction mixture gets hot
- colourless solution formed
Mg (s) + 2HCl(aq) –> MgCl2(aq) + H2(g)
Mg(s) + H2SO4(aq) –> MgSO4(aq) + H2(g)
observation of reaction with HCl or H2SO4 and equations: aluminium
- slow to start reacting when cold, but bubbles form when heated
- aluminium disappears
- colourless solution formed
2Al(s) + 6HCl(aq) –> 2AlCl3(aq) + 3H2(g)
22Al9s) + 3H2SO49aq) –> Al2(SO4)3(aq) + 3H2(g)
observation of reaction with HCl or H2SO4 and equations: zinc
- bubbles of gas
- zinc disappears
- colourless solution formed
Zn(s) + 2HCl(aq) –> ZnCl2(aq) + H2(g)
Zn(s) + H2SO4(aq) –> ZnSO4(aq) + H2(g)
observation of reaction with HCl or H2SO4 and equations: iron
- bubbles of gas
- iron disappears
- pale green solution formed
Fe(s) + 2HCl(aq) –> FeCl2(aq) + H2(g)
Fe(s) + H2SO4(aq) –> FeSO4(aq) + H2(g)
hydrogen burns when heated un air or oxygen to form…
water
2H2(g) + O2(g) –> 2H2O(l)
how to test for hydrogen
a mixture of hydrogen and air/oxygen will explode when ignited by a spark of a flame and water is the product. this provides the characteristic test for hydrogen. mix a test tube full of hydrogen with air and place the lame of a lighted spill at the mouth of the test tube, hear a squeaky pop
2 tests for pure water
- add the liquid from condensing the water vapour to anhydrous copper(II) sulphate. the white powder will turn blue and hydrated copper (II) sulphate is formed:
CuSO4(s) + 5H2O(l) –> CuSO4.5H2O(s)
white –> blue - boil the liquid and measure its boiling point (100 degrees Celsius).
theses two tests together confirm that the liquid is pure water. if the water contains impurities, its boiling point will be above 100 degrees celcius and its freezing point will be less than 0 degrees celcius
