C4 Flashcards
What are the group 1 elements also known as?
Alkali metals
What is the general trend in density down group 1?
Increasing
What is the general trend in melting point down group 1?
Decreasing
What is the general trend in reactivity down group 1?
Increasing
Explain the trend in reactivity down group 1.
Reactivity increases as you go down the group;
because the outer shell electron gets further from the nucleus;
so there is a weaker force of attraction between the outer shell electron and the nucleus;
so the outer shell electron is lost more readily
Which group 1 element reacting with water does this best describe?
Fizzes steadily and slowly dissapears
lithium
Which group 1 element reacting with water does this best describe?
melts to form a silver ball, fizzes vigourously and quickly disappears
sodium
Which group 1 element reacting with water does this best describe?
immediately ignites, burns with a lilac flame and very quickly disappears
potassium
What two products are formed when group 1 metals react with water?
hydrogen and a metal hydroxide
Would you expect the solution formed from the reaction of a group 1 metal with water to be acidic or alkaline?
alkaline
due to the formation of a metal hydroxide
What name are the group 17 (old group 7) elements known by?
The halogens
What name is given to a compound containing a group 17 (old group 7) element?
Halide
What is the general trend in reactivity of the halogens going down the group?
Decreasing
What is the general trend in melting and boiling points of the halogens going down the group?
Increasing
What is the general trend of the colours of the halogens going down the group?
Tend to get darker
What is the general trend in the density of the halogens going down the group?
Increasing
Explain the trend in reactivity of the halogens going down the group.
Reactivity decreases as you go down the group;
because the outer shell gets further from the nucleus;
so there is a weaker force of attraction between the outer shell electrons and the nucleus;
so electrons are gained less readily
Which halogens can displace other halogens from their halide compounds?
More reactive halogens can displace less reactive halogens from their halide compounds
Which halogens can displace iodine from NaI?
fluorine, chlorine and bromine
Which halogens can displace bromine from KBr
fluorine and chlorine
Which halogens can displace chlorine from KCl
fluorine
What are the products of this displacement reaction?
Cl2 + 2KBr –>
Cl2 + 2KBr –> 2KCl + Br2
What are the products of this displacement reaction?
F2 + 2NaI –>
F2 + 2NaI –> 2NaF + I2
What observations would you expect to make when adding aqueous chlorine solution to a solution of potassium bromide?
Colourless potassium bromide solution turns orange/brown
due to the formation of bromine
What name are the group 0 elements commonly known as?
The noble gases
What is the general trend in the density of the group 0 elements going down the group?
Increasing
What is the general trend in boiling points of the group 0 elements going down the group?
Increasing
Explain the lack of reactivity of the group 0 elements?
All group 0 elements have a full outer shell of electrons;
so they have no tendency to either gain or lose electrons;
so they don’t readily form ions or covalent bonds
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What are some general properties of all metals
Shiny when freshly cut;
good conductors of electricity;
malleable
In what ways do the properties of the transition metals differ from the group 1 metals?
Transition metals are stronger and harder;
have higher densities;
have higher melting points
except mercury which is a liquid at room temperature
Why do the compounds of transition metals sometimes include roman numerals in their formulae?
Transition metal elements often form several ions with different charges.
What name is given to the elements in groups 3 to 12 of the periodic table?
Transition metals
What test is used for carbon dioxide?
When carbon dioxide is bubbled through limewater, the limewater turns cloudy due to the formation of a white precipitate
What test is used for chlorine?
Chlorine turns damp blue litmus red, then bleaches it white.
What test is used for hydrogen?
When a lit splint is held to the mouth of a container filled with hydrogen, the hydrogen ignites with a squeaky pop
What test is used for oxygen?
A glowing splint will reignite when held in a container of oxygen
What flame test colour indicates lithium ions?
Red
What flame test colour indicates sodium ions?
yellow
What flame test colour inidcates potassium ions?
Lilac
What flame test colour indicates calcium ions?
Orange-red
What flame test colour indicates copper ions?
Green-blue
A red flame is indicative of which ion?
Li+
A yellow flame is indicative of which ion?
Na+
A lilac flame is indicative of which ion?
K+
An orange-red flame is indicative of which ion?
Ca2+
A green-blue flame is indicative of which ion?
Cu2+
A green precipitate during a hydroxide precipitate test indicates the presence of which ion?
Fe2+
An orange-brown precipitate during a hydroxide precipitate test indicates the presence of which ion?
Fe3+
An blue precipitate during a hydroxide precipitate test indicates the presence of which ion?
Cu2+
A white precipitate that does not redissolve in excess sodium hydroxide during a hydroxide precipitate test indicates the presence of which ion?
Ca2+
A white precipitate that redissolves in excess sodium hydroxide during a hydroxide precipitate test indicates the presence of which ion?
Zn2+
What colour precipitate is formed when sodium hydroxide is added to a solution containing iron(II) ions?
Green
What colour precipitate is formed when sodium hydroxide is added to a solution containing iron(III) ions?
orange-brown
What colour precipitate is formed when sodium hydroxide is added to a solution containing copper(II) ions?
blue
What colour precipitate is formed when sodium hydroxide is added to a solution containing calcium ions?
white
What colour precipitate is formed when sodium hydroxide is added to a solution containing zinc ions?
white
How can a zinc hydroxide precipitate be distinguished from a calcium hydroxide precipitate?
The zinc hydroxide precipitate will redissolve in excess sodium hydroxide, whislt the calcium hydroxide precipitate will not redissolve
What test is used for sulfate ions?
A white precipitate will form when barium chloride solution is added to a solution containing sulfate ions
the precipitate is insoluble barium sulfate
What test is used for carbonate ions?
A solution containing carbonate ions will effervesce when dilute acid is added
Due to the formation of carbon dioxide gas - test also works on solids
effervescence = bubbling
What test is used for chloride ions?
A white precipitate forms when silver nitrate solution is added to a solution containing chloride ions.
the precipitate is insoluble silver chloride
What test is used for bromide ions?
A cream precipitate forms when silver nitrate solution is added to a solution containing bromide ions.
the precipitate is insoluble silver bromide
What test is used for iodide ions?
A yellow precipitate forms when silver nitrate solution is added to a solution containing iodide ions.
the precipitate is insoluble silver iodide
An white precipitate during a silver nitrate test indicates the presence of which ion?
Cl-
An cream precipitate during a silver nitrate test indicates the presence of which ion?
Br-
An yellow precipitate during a silver nitrate test indicates the presence of which ion?
I-
Effervescene when dilute acid is added to a solution indicates the presence of which ion?
CO32-
A white precipitate when barium chloride is added to a solution indicates the presence of which ion?
SO42-
Why might you acidify a solution with hydrochloric acid before carrying out the barium chloride test?
To make sure any carbonate ions have reacted to form carbon dioxide first
otherwise a precipitate of barium carbonate could give a false positive
State three advantages instrumenta methods of analysis have over chemical methods of analysis.
greater sensitivity;
greater accuracy;
greater speed
In a gas chromatogram, what is represented by each peak
a substance present in the mixture
How many peaks would a gas chromatogram of a pure substance have?
one
How many peaks would a gas chromatogram of a mixture of three compounds have?
three
What feature of a gas chromatogram represents the relative amount of a substance?
The area under the peak
What is the time taken for a substance to travel through a gas chromatography column known as?
retention time
What are the three main uses of mass spectrometry?
measuring the mass of atoms and molecules;
determining the relative amounts of different isotopes of an atom;
determining the stucture of molecules
In a mass spectrum, what does the peak to the far right represent?
the molecular ion
In a mass spectrum, what do the peaks to the left of the right-most peak represent?
different fragments of the molecular ion
What quantity is measured on the horizontal axis of a mass spectrum
the mass to charge ratio
(m/z)
where m is mass and z is charge
What is the m/z ratio of the molecular ion equal to?
the relative formula mass (Mr) of the molecule
assuming at GCSE that the molecular ion has a +1 charge