Group 2 Flashcards

1
Q

Describe and explain the trend, down the group, of the reactivity of Group 2 with water. (5)

A
  • reactivity increases
  • atomic radii increases
  • more shielding
  • increased nuclear charge
  • ionisation energy decreases
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2
Q

Why are the second ionisation energies of calcium and strontium greater than their first ionisation energies? (1)

A
  • ion is smaller
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3
Q

Explain why barium is more reactive than calcium. (4)

A
  • Barium atoms are larger
    ^ more shielding
  • outweighs the increase in nuclear charge
  • ionisation energy decreases
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4
Q

Which Group 2 oxide produces a saturated solution with the highest pH?

A

BaO(aq)

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5
Q

State how a Group 2 element forms an ionic bond with non-metals.

A
  • by donating its 2 outer electrons
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6
Q

Are group 2 elements oxidising or reducing agents?

A

reducing.

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7
Q

Explain the trend in first ionisation energies as you move down Group 2. (4)

A
  • decreases
  • nuclear charge same
  • shielding increases
    ^ leads to weaker attraction between the nucleus & the outermost electrons
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8
Q

Describe the trend in alkalinity as you move down Group 2. (1)

A
  • increases
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9
Q

Describe the trend in the reactions of Group 2 with water. (1)

A
  • react more vigorously w/ water as you go down the group
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10
Q

Explain the trend in the first three ionisation energies of magnesium. (3)

A
  • ionisation energy increases
  • similar shielding
  • large increase b/w 2nd and 3rd IE because 3rd electron is being removed from 2p orbital rather than 3s orbital
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11
Q

Explain how the trend in solubility and strength as a base observed going down Group 2 are connected. (3)

A
  • solubility in water & strength as a base both increase down the Group
  • increasing solubility means that there’s more OH- ions in the solution
  • base strength is measured by the concentration of OH- ions.
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12
Q

Explain how the bonding in Beryllium Chloride differs from the rest of the Group 2 Chlorides. (4)

A
  • predominantly covalent
  • Be2+ = highest mass-charge ratio
  • so Be2+ polarises the Cl ion
  • causing the Cl ion to share its electron
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13
Q

Give the reagents required to test for and distinguish between the halide ions. (4)

A
  • dilute nitric acid
  • silver nitrate solution
  • dilute ammonia
  • concentrated ammonia
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14
Q

Define: disproportionation reaction

A
  • a reaction in which the same species is simultaneously oxidised and reduced.
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15
Q

Suggest why adding chlorine to the drinking water is safe to do so. (2)

A
  • it’s only added in small volumes
  • therefore not harmful to humans in those levels
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16
Q

Define: reducing agent

A
  • a species that can donate electrons
17
Q

Explain why an iodide ion is a better reducing agent than a bromide ion. (3)

A
  • an iodide ion is larger
  • therefore outermost electrons more shielded by inner shells
  • so outermost e- lost more easily
18
Q

Describe the test for: sulfate ions

A
  • add a few drops of aqueous barium chloride
  • if sulfate ions present, a white precipitate (barium sulfate) is formed
19
Q

Describe the test for: ammonium ions

A
  • react w/ warm aqueous sodium hydroxide
  • ammonia will turn damp litmus paper blue
20
Q

Explain why fluorine has a lower b.p than chlorine. (2)

A
  • flourine = smaller than Cl
  • forces b/w flourine molecules = weaker
21
Q

Predict the order of melting points for: (6)
- chlorine (Cl)
- iodine monochloride (ICl)
- sodium chloride (NaCl)

A
  • Cl = lowest m.p , NaCl = highest m.p
  • Cl = weak induced dipole-dipole forces only
  • ICl = polar molecule w/ permanent dipole-dipole forces between molecules
  • permanent d.ps stronger than induced d.ps but weaker than ionic bonds in NaCl
  • NaCl = strong ionic bonds b/w ions
  • ionic bonds = strongest of all bonds present
22
Q

Explain why bromine is a liquid at room temperature but fluorine and chlorine are gases. (3)

A
  • Br = higher b.p than F & Cl
  • more electrons in molecules of Br
  • so more energy required to pull Bromine molecules apart
23
Q

Explain the different boiling points of NH3, F2 and Br2. (5)

A
  • NH3 = hydrogen bonding b/w molecules
  • F2 & Br2 = both induced d.p-d.p
    ^ induced d.ps in Br2 = stronger bcs Br2 has more electrons
  • induced d.p force in Br2 = stronger than hydrogen bonding in NH3
  • hydrogen bonding in NH3 stronger than induced d.ps in F2
24
Q

State one advantage and one disadvantage of using chlorine in water treatment. (2)

A

advantage:
- Cl kills bacteria

disadvantage:
- Cl is toxic

25
Q

Explain why iodine is a weaker oxidising agent than bromine. (3)

A
  • I = larger atomic radius
  • & more shielding
  • I has a weaker nuclear attraction
26
Q

Explain why it’s important NOT to add any household cleaning agents that contain hydrochloric acid to a solution of bleach. (2)

A
  • NaClO reacts with HCL to produce chlorine gas
  • which is toxic