[🧪] Group 2 Flashcards

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1
Q

Describe and explain the trend in

atomic radius in Group 2?

[🧪] Group 2

A

down the group, atomic radius increases

[🧪] Group 2

  • Down the group, nuclear charge increases while atoms have more electron shells so they experience more shielding effect.
  • Thus, there is less nuclear attraction for the valence electrons, so atomic radius increases.
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2
Q

What is the trend in

melting point in Group 2?

[🧪] Group 2

A

down the group, melting point decreases

[🧪] Group 2

  • Down the group, ionic radius increases, so the distance between cations and delocalised electrons increase.
  • Thus, electrostatic forces of attraction between cations and delocalised electrons decreases and metallic bonding weakens.
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3
Q

What is the trend in

solubility of Group 2 hydroxides?

[🧪] Group 2

A

down the group, solubility of Group 2 hydroxides increases

[🧪] Group 2

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4
Q

What is the trend in

first ionisation energy in Group 2?

[🧪] Group 2

A

down the group, first ionisation energy decreases

[🧪] Group 2

  • Down the group, nuclear charge increases while the nucleus experiences more shielding.
  • Nuclear attraction for the valence electrons decreases, so less energy is required to remove the first electron.
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5
Q

What is the trend in

reactivity in Group 2?

[🧪] Group 2

A

down the group, reactivity increases

[🧪] Group 2

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6
Q

General formula for

Group 2 + O₂

[🧪] Group 2

A

2M + O₂ → 2MO

[🧪] Group 2

Sr and Ba also form MO₂

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7
Q

[🧪] Group 2

2Mg + O₂

observations

A

burns easily with a bright white flame

[🧪] Group 2

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8
Q

[🧪] Group 2

2Ca + O₂

observations

A

difficult to ignite, red flame

[🧪] Group 2

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9
Q

[🧪] Group 2

2Sr + O₂

observations

A

difficult to ignite, red flame

[🧪] Group 2

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10
Q

[🧪] Group 2

2Ba + O₂

observations

A

difficult to ignite, green flame

[🧪] Group 2

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11
Q

General formula for

Group 2 + H₂O

[🧪] Group 2

A

M + 2H₂O → M(OH)₂ + H₂

[🧪] Group 2

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12
Q

General formula for

Group 2 + HCl

[🧪] Group 2

A

M + 2HCl → MCl₂ + H₂

[🧪] Group 2

Colourless metal chloride solutions are formed

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13
Q

General formula for

Group 2 + H₂SO₄

[🧪] Group 2

A

M + H₂SO₄ → MSO₄ + H₂

[🧪] Group 2

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14
Q

[🧪] Group 2

Mg + 2H₂O

speed

A

with steam → vigorous reaction
with water → slow reaction

[🧪] Group 2

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15
Q

[🧪] Group 2

Ca + 2H₂O

speed

A

reacts moderately

[🧪] Group 2

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16
Q

[🧪] Group 2

Sr + 2H₂O

speed

A

reacts rapidly

[🧪] Group 2

17
Q

[🧪] Group 2

Ba + 2H₂O

speed

A

reacts vigorously

[🧪] Group 2

18
Q

[🧪] Group 2

M + 2HCl

observatons

A
  • all Group 2 metals react with HCl vigorously
  • colourless metal salt solutions are always produced

[🧪] Group 2

19
Q

Trend in

solubility of Group 2 sulfates

[🧪] Group 2

A

down the group, solubility of sulfates decreases

[🧪] Group 2

20
Q

[🧪] Group 2

Mg + H₂SO₄

speed

A

reacts vigorously

[🧪] Group 2

21
Q

[🧪] Group 2

Ca + H₂SO₄

speed

A

reaction slowed down by a sparingly soluble sulfate layer which coats the metal’s surface, stopping hydrogen bubbles from rising

[🧪] Group 2

22
Q

[🧪] Group 2

Sr + H₂SO₄

speed

A

reaction quickly stopped by insoluble sulfate layer on the metal’s surface

[🧪] Group 2

23
Q

[🧪] Group 2

Ba + H₂SO₄

speed

A

reaction quickly stopped by insoluble sulfate layer on the metal’s surface

[🧪] Group 2

24
Q

[🧪] Group 2

Exceptions for Group 2 + H₂O

A
  • For Mg, MgO and H₂ are formed instead
  • Beryllium doesn’t react with water
25
Q

General formula for

Group 2 oxide + H₂O

[🧪] Group 2

A

MO + H₂O → M(OH)₂

but aqueous for Sr & Ba

Hydroxide is solid for Mg & Ca, aqueous for Sr & Ba

26
Q

[🧪] Group 2

Notes for MgO reacting with H₂O

A

MgO is slightly soluble in water
Thus, weakly alkaline solution is formed

27
Q

[🧪] Group 2

CaO + H₂O

observations

A
  • vigorous reaction
  • some water boils off
  • solid lump expands and opens up
28
Q

General formula for

Group 2 oxide + HCl

[🧪] Group 2

A

MO + 2HCl → MCl₂ + H₂O

29
Q

General formula for

Group 2 oxide + H₂SO₄

[🧪] Group 2

A

MO + H₂SO₄ → MSO₄ + H₂O

30
Q

[🧪] Group 2

How can you prevent insoluble sulfate from forming as a result of reacting
Group 2 metal oxide and H₂SO₄?

A

Perform the reaction by stirring powdered oxide in the H₂SO₄

31
Q

Describe and explain the trend in

alkalinity of hydroxides down Group 2

[🧪] Group 2

A

down the group, alkalinity of hydroxides increases

  • down the group, solubility of hydroxides increases, causing the concentration of OH- ions that dissociate in solution to increase
  • this increases the pH of the solution and thus its alkalinity
32
Q

General formula for

Group 2 carbonate + HCl

[🧪] Group 2

A

MCO₃ + 2HCl → MCl₂ + H₂O + CO₂

33
Q

General formula for

Group 2 carbonate + H₂SO₄

[🧪] Group 2

A

MCO₃ + H₂SO₄ → MSO₄ + H₂O + CO₂

34
Q

General formula for

the thermal decomposition of Group 2 carbonates

[🧪] Group 2

A

MCO₃ → MO + CO₂

35
Q

Describe and explain the trend of

thermal decomposition of Group 2 carbonates

[🧪] Group 2

A

down the group, thermal stability of Group 2 carbonates (and nitrates) increases

  • down the group, charge is constant while charge density decreases and shielding effect increases
  • so the radius of the cation increases
  • the polarising ability of the cation decreases
  • so the anoin is less polarised
36
Q

Describe and explain the trend of

thermal decomposition of Group 2 nitrates

[🧪] Group 2

A

down the group, thermal stability of Group 2 nitrates (and carbonates) increases

  • down the group, charge is constant while charge density decreases and shielding effect increases
  • so the radius of the cation increases
  • the polarising ability of the cation decreases
  • so the anoin is less polarised
37
Q

General formula for

the thermal decomposition of Group 2 nitrates

[🧪] Group 2

A

2M(NO₃)₂ → 2MO + 4NO₂ + O₂

38
Q

[🧪] Group 2

M(NO₃)₂ thermal decomposition

observations

A

a brown, toxic gas is released