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Flashcards in Group 16 Deck (35)
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1
Q

What types of elements does group 16 contain?

A

Non-metals, semi-conductors and metallics.

2
Q

What is catenation?

A

Bonding of the same element in series to form a chain..

3
Q

What is the maximum oxidation state for group 16?

A

+6.

4
Q

What are the common oxidation states of oxygen?

A

-2, -1 and 0.

5
Q

What is a triplet ground state?

A

The idea that the element has two spins of a half, and the total spin is defined as 2s+1 = 3.

6
Q

What are the properties of oxygen when solid or liquid?

A

Pale blue - at low temperatures.

7
Q

Why is oxygen paramagnetic?

A

It contains two unpaired electrons in its MO diagram.

8
Q

What is the significance of the higher Zeff in oxygen than nitrogen?

A

The s orbital is dragged down further in energy than the P - there is no s-p mixing.

9
Q

How is ozone prepared?

A

Electrical discharge through O2.

10
Q

What is the bond order of o-o bonds in O3?

A

1.5 - there is a half bond per O-O.

11
Q

What is the bonding in ozone?

A

The central O is sp2 hybridised - there is a lone pair of electrons in an Sp2 hybrid and a lone pair of electrons in a p orbital. There is a total of 4 electrons in p orbitals.

12
Q

What is the bond length in ozone?

A

Shorter than a single bond but longer than a double bond.

13
Q

Is oxygen or ozone a stronger oxidising agent?

A

Ozone - has a higher Eo.

14
Q

Why does elemental S have many allotropic forms?

A

It has a large number of rings and that can be formed with S-S bonds and the many ways they can pack in the solid state.

15
Q

What happens if you heat S8?

A

It melts and forms a yellow liquid (119 degrees) and then if it is continued to be heated to 159 degrees the viscosity increases dramatically. THe s8 rings open to form S8 chains. These interact to form S16, S24 etc and then if it is heated further the viscosity decreases again.

16
Q

Why is N2 more stable than P2 is they both have a short triple bond?

A

THe bond energy of N2 is more than 3x that for a N-N single bond. N-N allotropes are unstable with respect to N2. P2 does not show this property.

17
Q

What happens to atom size down the group?

A

It increases, and therefore atom-atom contact also increases.

18
Q

What happens to bond strength down the group and why?

A

As atom size increases, the size of the orbitals also increases and the distance them increases. The bond strength therefore also decreases.

19
Q

Why does the bond energy across the period decrease for N O and F?

A

The presence of lone pairs and the small size of the atoms causes stronger repulsions.

20
Q

What happens to acidity down a group of EH compounds?

A

It increases as the bonds are weaker and there is a greater tendency to form H+.

21
Q

Why is S2 made up of two sigma bonds whereas O2 is made up of a sigma and pi?

A

The pi component for O2 is greater than the sigma component - this is not true for S2 so it is more energetically favourable to have 2 sigma bonds.

22
Q

What happens to the energy differences between s and p orbitals down the group?

A

The energy difference increases and there is less s-p mixing and the bonds become more p like in character.

23
Q

Why does the boiling point of S to Te increase?

A

There is more Van der Waal’s forces.

24
Q

What are the properties of water?

A

The solid has a lower density than the liquid so ice floats, there are least 9 different forms at atmospheric pressure and 0 degrees, hexagonal ice exists.

25
Q

What are the properties of H2O2?

A

It is a very pale blue liquid with a boiling point of 150 degrees, it is a liquid at room temperature and is more viscous and dense than H20, the oxidation state is -1 and it can be both a strong oxidising and reducing agent.

26
Q

What is the only halide possible for oxygen?

A

Fluoride.

27
Q

What are the properties of OF2?

A

It is a colourless gas that is toxic and undergoes rapid decomposition to F2 and O2.

28
Q

What is the boiling point of OF2?

A

-145 degrees celsius.

29
Q

What are the properties of OFH?

A

It is a colourless liquid that is very toxic. It decomposes to HF and O2 at room temperature.

30
Q

What is the boiling point of OFH?

A

29 degrees celsius.

31
Q

How can O2F2 be prepared?

A

Passing electrical discharge through F2 and O2.

32
Q

What do elements below the top row have the ability to do?

A

Expand the octet/show hypervalency.

33
Q

What was the old argument for why the second row elements show hypervalency?

A

Electrons went into d orbitals - this is wrong as there is a huge energy gap.

34
Q

What is the modern idea for why second row elements show hypervalency?

A

The additional electrons go into non-bonding orbitals.

35
Q

Why is SF6 stable?

A

The fluorine atoms surrounding the sulfur stop attack at the centre.