Inorganic Chemistry & The PT Flashcards

1
Q

What is the outer shell electron configuration of the halogens?

A

s2 p5

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2
Q

Room temperature appearance of fluorine

A

Yellow gas

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3
Q

Room temperature appearance of chlorine

A

Green gas

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4
Q

Room temperature appearance of bromine

A

Brown liquid

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5
Q

Room temperature appearance of iodine

A

Dark grey solid

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6
Q

Describe the trend in boiling points down group 7

A

Boiling points increase: number of electrons increase; more London forces; more heat energy needed to break these intermolecular forces

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7
Q

Electronegativity def

A

The ability of an element to draw a pair of bonding electrons towards itself in a covalent bond

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8
Q

Describe the trend of electronegativity down group 7

A

Electronegativity decreases: more protons means an increasing nuclear charge should attract outer electrons more; number of electron shells increases and so there is more shielding; atomic radius increases then means less nuclear attraction for outer electrons

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9
Q

Describe the trend of atomic size in group 7

A

Increases: greater atomic radius means more electrons; more electron shells so distance between outer electrons and nucleus increases

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10
Q

Describe the trend of ionic size down group 7

A

Increases: these ions (anions) are larger than atoms; added electrons to the same nuclear charge causes repulsion from other electrons, expanding the radius

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11
Q

Describe the trend of reactivity in group 7

A

Decreases: decreasing tendency to gain electrons; increasing nuclear charge as more protons should attract outer electrons more; but more electrons means more sheets and shielding; so atomic radius increases; less positive nuclear charge is experienced by outer electrons

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12
Q

Oxidising agents def + eg

A

Something that causes other substances to oxidise and is itself reduced e.g. Group 7 elements readily accept an electron to form negative ions

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13
Q

What is the trend in oxidisation for group 7?

A

Decreases: fluorine is a strong oxidising agent whereas iodine is fairly weak

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14
Q

What is the half equation for group 7 elements?

A

Reduction reaction: X2 + 2e- —> 2X-

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15
Q

Displacement reactions def (in group 7)

A

When a more reactive halogen displaces a less reactive one from its halide salt

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16
Q

How do halogens displace each other?

A

Cl2 oxidises 2Br- to Br2 and 2Cl-
Cl2 oxidises 2I- to I2 and 2Cl-
Br2 oxidises 2I- to I2 and 2Br-
Iodine does not react with bromides or chlorides

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17
Q

Solubility of halogens

A

All halogens dissolve readily in non-polar solvents; solute and solvent molecules have the same type of intermolecular attraction; new attractions are able to replace the previous ones (like dissolves like); only slightly soluble in polar molecules of water

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18
Q

Colour of halogen solutions in water

A

Cl - pale green
Br - orange
I - pale brown

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19
Q

Colour of halogen solutions in cyclohexane

A

Cl - pale green
Br - orange
I - violet

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20
Q

Halogen reaction with metals (equation eg)

A

Ha2 + 2Me —> 2MeHa

Produces metal halides

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21
Q

Disproportionation reaction def

A

When the same species is both oxidised and reduced in a reaction

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22
Q

Health benefits of chlorine use in water

A

Treatment of water in making it potable; powerful oxidising nature; effective disinfectant and kills bacteria; prevent a spread of water-borne diseases.
Bleach; decolourises water

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23
Q

Describe the trend in first ionisation energies in group 2

A

Decreases: atomic radius increase as number of electron shells increases; more shielding so weaker attraction between outer electrons and nucleus; less energy needed to lose outer electrons. The increase in number of protons is negated by increase in atomic charge and shielding.

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24
Q

Describe the trend in reactivity in group 2

A

Increases: atomic radius increases; more shielding; less attraction; outer two electrons more easily lost

25
Q

General equation of group 2 metals reacting with water

A

M(s) + 2H2O(l) —> M(OH)2(aq/s) + H2(g)

26
Q

When phosphorous reacts in a limiting supply of any halogen, what is formed?

A

Phosphorous trihalide

3Ha2 + 2P —> 2PHa3

27
Q

What phosphorous reacts in an excess of any halogen, what is formed?

A

Phosphorous pentahalide

5Ha2 + 2P —> 2PHa5

28
Q

How would you identify metal ions using flame tests?

A

Clean a platinum or nichrome wire in concentrated hydrochloric acid and place it in the hottest part of the Bunsen flame until it produces no colour. Moisten the wire in the acid and dip it in a sample of the powered solid being tested. Place in the flame and note the colour. Alternatively, spay a solution if the salt and ethanol in the flame.

29
Q

Flame test colour of lithium

A

Red (crimson)

30
Q

Flame test colour of sodium

A

Yellow

31
Q

Flame test colour of potassium

A

Lilac

32
Q

Flame test colour of calcium

A

Red orange / brick red

33
Q

Flame test colour of strontium

A

Red

34
Q

Flame test colour of barium

A

Pale green (apple green)

35
Q

How are colours produced in flame tests?

A

Electrons in the metal ion gain kinetic energy when heated so much that they can jump an energy level into an empty orbit. The electrons are now at a more energetically unstable level so they tend to fall back to their originals level. This releases energy in the form of visible light but at different frequencies due to the different gaps between levels to give particular colours.

36
Q

Bleaching def

A

The removal of colour from a substance. This is achieved by adding oxidising agents such as chlorine since coloured material often become colourless when oxidised

37
Q

Examples of reducing agents

A

Iron (II) compounds. Chlorine reacts with these ions to form iron (III) ions

38
Q

Halogens reactions with thiosulfate (S2O3^2-)

A

Chlorine and bromine both oxidise the sulfur from +2 in the thiosulfate ion to +6 in the sulfate ion. Iodine oxidises thiosulfate ions to tetrathionate ions (S4O6^-2) with sulfur’s oxidation number of 2.5

39
Q

Test for chlorine

A

Bleaches damp litmus paper (turns white).
Bubble through a potassium bromide solution. The colourless solution turns orange because the bromide ions are displaced and bromine is formed.

40
Q

Test for bromine

A

Damp litmus paper is slowly bleached.
Bubble through potassium iodide solution. The colourless solution turns red-brown because the iodide ions are displaced and iodine is formed.

41
Q

Test for iodine

A

Add to starch solution which will turn it dark solution

42
Q

Which halide compounds are insoluble in water?

A

Silver halides and lead (II) halides

43
Q

Reaction of hydrogen halides with water

A

Hydrogen halides are acids and react with water to form hydroxonium ions (H3O^+). The H-Ha bond is broken. This strength decreases down the group.

44
Q

Why is HI the strongest acid out of the three hydrogen halides in reacting with water?

A

It will lose a proton the easiest due to having the weakest bonds

45
Q

Reaction and use of ammonia with hydrogen halides

A

Used to test for hydrogen halides but it can’t distinguish between them. It produces misty white fumes NH4Ha

46
Q

Test for distinguishing between the halide ions (process)

A

Add dilute HNO3 to the solution. Add a few drops of silver nitrate. Add dilute ammonia solution to the precipitate formed. If the precipitate doesn’t dissolve, add concentrated ammonia solution

47
Q

Test for distinguishing between the halide ions (results) - with silver nitrate, dilute ammonia and concentrated ammonia

A

Silver nitrate - Cl: white, Br: cream, I: yellow
Dilute ammonia - Cl: soluble, Br: insoluble, I: insoluble
Concentrated ammonia - Cl: soluble, Br: soluble, I: insoluble

48
Q

Reducing ability of hydrogen halides

A

Increases down the group because the bond strength decreases

49
Q

How do group 2 metals react with water?

A

Form slightly soluble hydroxides (low concentration). Magnesium reacts slowly with cold water but rapidly with steam. Ca, St and Ba react with cold water at an appreciable rate

50
Q

What is the trend in solubility of group 2 oxides?

A

Increases down the group. The solubility of the hydroxides formed also increases as does the alkalinity of the solution formed

51
Q

Why is the first ionisation energy of hydrogen less than that of helium but greater than that of lithium?

A

Helium has more protons and therefore a greater nuclear charge than hydrogen and has its outer electrons in the same shell. Lithium is in period two so the outer electron is at a higher energy level meaning there is more shielding by inner electrons.

52
Q

What are the limitations and benefits of placing hydrogen above lithium in the periodic table?

A

Hydrogen is not a metal. It doesn’t react in the same way as the rest of the group 1. However it also has one electron in its outer shell like the other group 1 elements.

53
Q

Do transition metals from white compounds?

A

No. They are normally coloured

54
Q

What is the test for water?

A

Turns white copper sulphate blue

55
Q

Why is argon used in lamps?

A

Because it provides an inert atmosphere when reacting with oxygen so the lamp won’t catch fire

56
Q

What is the equation for the reaction of chlorine with cold, dilute sodium hydroxide solution to form bleach?

A

2NaOH + Cl2 —> NaCl + NaClO + H2O

57
Q

What is observed when hydrogen bromide gas reacts with ammonia gas?

A

Misty white fumes/white smoke

58
Q

In a mass spectrometer analysis of bromine Br2 with isotopes Br-79 and Br-81 present, why is there a small peak at m/z 80?

A

Br2 has a mass of 160 (as well as 158 and 162). This comes from a molecule of Br-79 and Br-81. The Br2^2+ ion has an m/z of 80

59
Q

What anhydrous compound can be used as a drying agent?

A

(Sodium) sulfate