IO1: Inorganic Flashcards
In terms of the periodic table, where are the blocks found?
s- left
d- middle
p- right
f- bottom
(outer electrons in these orbitals)
Do groups or periods have similar chemical properties?
Groups
Periods are arranged…
Periodically, as they have repeating patterns or periodic trends
In terms of the periodic table, where are metals and non-metals?
Metals- left and middle until the…
Metalloids- diagonal B, Si, As, Te, At, separates metals and non-metals
Non-metals- right
What is a metalloid?
Show some chemical properties of a metal, but is not a metal.
What is the trend in atomic radius of group 2?
Increases down
What is the trend in 1st ionisation energy of group 2?
Decreases down
How do the group 2, alkaline earth metals bond?
Metallically
What state are the group 2 metals at room temp?
Solid
What is the trend in melting point of group 2 metals?
Decreases down
-Metallic bonds get weaker
-Apart from Magnesium, which is lower than all group 2 metals
How do the group 2 metals react with water?
Going down, each reacts more vigourously.
-This is because 1st IE decreases down the group, so easier to lose electrons (decrease activation energy)
Which group 2 metal does not react with water?
Be
How does Mg react with water?
Only slightly, but does rapidly react with steam and gives off a bright light.
Group 2 + water =?
Metal Hydroxide
Magnesium can be used to extract Ti from its ore, explain how.
- TiO2 is heated with carbon and chlorine to form titanium chloride
- Reduced by Mg where Mg donates its electrons to Ti, making Ti and magnesium chloride.
Mg= reducing agent
How is calcium used to prevent acid rain?
Burning fossil fuels gives off SO2 which causes acid rain.
-Spraying ‘slurry’ of calcium carbonate, or calcium oxide over sulfur dioxide gas, and collects the calcium sulfide that forms.
What is the solubility of Group 2 Hydroxides?
Increases down the group
Magnesium hydroxide is hardly soluble, so is a white precipitate
What group 2 hydroxide can be used to cure heartburn and why?
Magnesium Hydroxide- Mg(OH)2
-Base is strong enough to neutralise the pH of stomach
-Low solubility means it is not strong enough to damage body.
What group 2 hydroxide neutralises soil?
Calcium hydroxide - Ca(OH)2
-‘slaked lime’
-strong base to neutralises pH
Hydroxide solubility increases, sulfate solubility…
Decreases
What is Barium sulfate used for and why?
(Barium Meal)
Consumed before an X-ray as it insoluble but dense.
What is Barium Chloride used for?
To test for sulfate ions.
-When acid is added to removes carbonate, forms a white precipitate.
Are group 7 Halogens reactive?
Very
Halogen + metal =?
Salts
What is a halide?
When halogens gain an electron and become ions e.g chloride, fluoride
What is fluorine at room temp?
Pale yellow gas
What is chlorine at room temp?
Green gas
What is bromine at room temp?
Red/brown liquid
What is iodine at room temp?
Black or dark grey solid
What is astatine at room temp?
Black or dark grey solid
All halogens form ______ molecules
Diatomic
What is the trend in electronegativity of group 7 and why?
Decreases down
-More full shells, increases shielding, increases atomic radius, electron pair is further away from nucleus
-This outweighs increase in nuclear charge.
What is the trend in boiling point of group 7?
Increases down
-More mass, electrons, size, surface area
-Stronger VDW forces
-More energy needed to overcome forces
Describe the oxidising ability of halogens
Decreases down, fluorine being the best
-tend to gain an electron (halides)
-oxidising agents in redox, become 1- ions.
-in a displacement reaction, fluorine will always displace another halogen.
Describe the reducing ability of Halides
Increases down the group, iodide the best
Discuss the reducing ability of NaBr with sulphuric acid
Acid-base reaction= HBr, a steamy gas
Redox reaction= Br2, a brown steamy gas
Discuss the reducing ability of NaI with sulphuric acid
Acid-base reaction= HI, steamy fumes
Redox reaction= H2S, yellow solid or rotten eggs smell,
or I2, dark grey solid
What would you use to identify halides?
Silver nitrate
What happens to the halides when silver nitrate is added to them dissolved in water?
F- = no ppt (soluble)
Cl- = white ppt
Br- = cream ppt
I- = pale yellow ppt
become silver fluoride…
If the halide has impurities, what can you react it with?
Dilute nitric acid
-gets rid of carbonates and forms CO2 and H2O
What are the further tests to adding silver nitrate to halides, that help us identify?
Dilute ammonia:
Cl- = colourless
Br- = cream
I- = pale yellow
Concentrated ammonia:
Cl- = colourless
Br- = colourless
I- = pale yellow
Cl2 + water =?
Dissociates to form Cl- ions, forming either:
HCl (hydrochloric acid)
HClO ( chloric 1 acid)
-a disproportionation reaction
What does HClO dissociate to and how is it useful?
H+ and ClO-
ClO- (chlorate ion) is an oxidising agent that is toxic and will kill bacteria (used in chlorination).
What are the pros and cons of chlorination?
+Kept at harmless concs
+Saved millions of lives
-Toxic
-Wasteful (only 1% of water we drink)
Write the chemical equation for the disproportionation of chlorine and water
Cl2 + H2O <> HCl + HClO
<>= reversible reaction
What happens when sunlight is a factor in the chlorine + water reaction?
Produces HCl + O2
There is no HClO to kill bacteria, a problem in pools
Bleach is an oxidising agent, how is it formed?
Chlorine + cold, dilute sodium hydroxide
forms NaClO
What happens to the atomic radius across period 3 and why?
Decreases
More protons in the nucleus, an electrostatic attraction to electrons, pulling them in, decreasing size.
Describe the trend in First ionisation energy across period 3.
Increases across, due to increase in nuclear charge.
Dip between Mg and Al: electrons start to fill the p-sub shell in Al, so a small increase in shielding, less energy to remove an electron.
Dip between P and S: in group 5, each p sub unit has one electron in it but in group 6 there is 2, so spin pair repulsion occurs, already repel each other making it easy to remove.
What is the bonding of the period 3 elements?
Na, Mg, Al: metallic
Si: Giant covalent lattice (metalloid)
P, S, Cl: covalent
Describe the trend in melting points for metals of period 3
Melting point increases going across as the metal cations have a higher charge, so number of delocalised electrons increases, more electrostatic attraction, higher temps needed.
Describe the covalent bonding in silicon
-Can bond to any number of other silicon atoms, so can make a giant covalent lattice
-A macromolecule
What molecule does phosphorus go around as?
P4
Describe the trend in melting points of the non-metals in the period 3 elements
Highest:
Silicon- giant covalent lattice, strong bonds
Sulphur- simple molecule, more VDW due to size
Phosphorus- less VDW
Chlorine- even less VDW
Argon- no molecules
Lowest
What molecule does sulphur go around as?
S8
What trend can we/ can not generalise to other periods?
Can:
-Atomic radius
-1st IE
Cannot:
-Melting points
What reaction proves group 7s oxidising ability?
Displacement
More reactive halogen (better oxidising agent) takes the place of a less reactive halide ion (better reducing agent)
Explain how to do the displacement reactions to prove group 7s oxidising ablilities
Chlorine water with…
NaCl - colourless
NaBr- orange/yellow
NaI- Brown
How do you prove the reducing abilities of group 7?
React with sulphuric acid (H2SO4)
Explain how to do the reaction with group 7 and sulphuric acid to prove reducing ability
Conc H2SO4 with…
NaCl - misty white fumes
NaBr- misty white, or orange fumes
NaI- misty white, or grey solid/ rotten eggs smell
