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Flashcards in Periodicity Deck (22)
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0
Q

What is the least electronegative element?

A

Francium (0.7)

1
Q

What is electronegativity?

A

A measure of the ability of an atom in a covalent bond to attract the electron bond pair

2
Q

Why does electronegativity increase across a period?

A

Nuclear charge increased while radius decreases

3
Q

Why does electronegativity decrease down any group?

A

As each element has an extra shell of electrons and a greater radius
Thus, less attraction for outer shell electrons

4
Q

What is ionisation energy?

A

The energy needed to remove one mole of electrons from one mole of atoms or molecules in gaseous phase

5
Q

How reactive is an element with the low IE?

A

Very reactive as it is easier to remove an electron

6
Q

Generally ionisation energy increases across a period- why?

A

Nuclear charge increases with each added proton, while with little extra shielding.
Atomic radius decreases so more energy is needed to remove each electron

7
Q

What are the anomalies of ionisation energy trends?

A

Group 2 to group 3 decreases as there is shielding by full s subshell
Be/B Mg/Al

N to O decrease as N has a half filled p subshell whereas O has slight e- pair repulsion = O’s electrons are lost more easily

8
Q

Why does Aluminium have a higher melting point than other metals?

A

It has 3 delocalised electrons, therefore stronger attractions and smaller atomic cores

9
Q

Describe the solubility of group 1 compounds

A

All are soluble

10
Q

Is Mg(OH)2 soluble or insoluble?

A

Insoluble

11
Q

How soluble is MgSO4?

A

Soluble

12
Q

Are group 2 carbonates soluble?

A

No, all insoluble.

13
Q

Is BaSO4 soluble?

A

No, insoluble

14
Q

Give 2 balanced equations to show the amphoteric nature of Al2O3

A

With an acid
Al2O3 + 3H2SO4 -> 2Al2(SO4)3 + 3H2O

With a base
Al2O3 + 3H2O + 2NaOH -> 2NaAl(OH)4

15
Q

Is Al2O3 soluble or insoluble?

A

Insoluble so doesn’t affect pH of water

16
Q

What is the formula for Berylliumhydroxide?

A

Be(OH)2

17
Q

What is the bonding in Be(OH)2 and why?

A

Ionic
High electronegativity
High charge density in Be2+ ion high polarises the anion- so has a covalent character in salts

18
Q

Give two equations to show the amphoteric nature of Be(OH)2

A

With acid-
Be(OH)2 + 2HCl -> BeCl2 +2H2O
With base-
Be(OH)2 + NaOH -> Na2Be(OH)4

19
Q

What elements show amphoteric behaviour?

A

Zn, Be, Al, Sn and Pb

20
Q

What type of chloride reacts with water?

Give an example (with balanced eqn)

A

Covalent chlorides

PCl5 + H2O -> HCl + H3PO4

21
Q

How do PCl3 and PCl5’s reaction with water differ?

A

PCl3 produces HCl and H3PO3

PCl5 produces HCl and H3PO4