Group 2, the alkaline earth metals Flashcards

1
Q

How does atomic radius change down group 2

A

It increases as each element has an extra level of electrons filled

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2
Q

How does ionisation energy change down group 2

A

Decrease down the group as outer shell electrons get further away. There is more shielding

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3
Q

How does melting and boiling point change down group 2

A

Decreases as the sea of delocalised electrons are further away from the positive nuclei

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4
Q

What happens when group 2 elements are put in water (redox)

A

They are oxidised as they want to lose 2 electrons

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5
Q

How does reactivity with water change down group 2

A

Metals get more reactive down the group

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6
Q

What is the general equation for a group 2 reaction with water

A

M + 2H2O —> M(OH)2 + H2

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7
Q

What is the equation for magnesium reacting with steam? Is it fast or slow?

A

Mg + H2O —> MgO + H2
Fast

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8
Q

What is Mg(OH)2 used for

A

Neutralises excess stomach acid which causes heart burn

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9
Q

What is the equation for magnesiums reaction with water? Is it fast or slow

A

Mg + 2H2O —> Mg(OH)2 + H2
Very slow

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10
Q

What is Ca(OH)2 used for

A

Used to treat acidic soil

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11
Q

How is magnesium used in the extraction of titanium TiCl4

A

TiCl4 + 2Mg —> 2MgCl2 + Ti

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12
Q

What is the trend in hydroxide solubility down group 2

A

Hydroxides become more soluble down the group

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13
Q

How can Mg(OH)2’s solubility be decribed

A

Sparingly soluble

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14
Q

What can CaO and CaCO3 be used for

A

Removing SO2 from flue gasses

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15
Q

What is the trend in sulphate solubility down group 2

A

They become less soluble down group 2

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16
Q

How soluble is Barium Sulphate (BaSO4)

A

It is insoluble

17
Q

What is Acidified BaCl2 used for?

What is a positive result?

A

The test for sulphate ions
A white precipitate is a positive result

18
Q

What is BaSO4 used for

A

Barium sulphate can be used in X-rays as it is opaque to x-rays meaning that the rays won’t pass through it
It is very insoluble so won’t be absorbed

19
Q

Why is BaCl2 used to test for sulphate ions and why must it be acidified

A

The sulfate ions displace the chloride ions, forming the insoluble salt barium sulfate

The acid reacts with any carbonate ions that could give a false positive

20
Q

Compare the pH of Mg(OH)2 and Ca(OH)2

A

Ca(OH)2 is higher as more soluble