3.3 Chemistry of the p-block Flashcards
Why are they called the p-block elements?
Each of the p-block elements have their outer electron in the p orbital.
What is meant by amphoteric behaviour?
An amphoteric species can act as both an acid and a base.
Which two p-block elements have amphoteric behaviour?
Al/Al3+
Pb/Pb2+
What is the chemical equation for the reaction between aluminium oxide and sulfuric acid?
What is the chemical equation for the reaction between aluminium oxide and sodium hydroxide?
What is the chemical equation for the reaction between lead oxide and hydrochloric acid?
What is the chemical equation for the reaction between lead oxide and sodium hydroxide?
What is the inert pair effect?
The tendency of electrons in the outer s orbital to remain unionised and unshared. It is used to explain the increasing stability of the oxidation states that are two less than the group valency for Groups 3, 4, and 5 (also known as Groups 13, 14 and 15).
Describe how the stability of oxidation states changes down Group 3
- In Group 3 (Group 13) the stability of the +1 oxidation state increases down the group.
- The Tl+ ion is much more common than the Tl3+ ion, whereas at the top of the group the Al+ ion is very rare due to its instability and hence the Al3+ ion is more common.
Describe how the stability of oxidation states changes down Group 4
In Group 4 (Group 14), stability of the +4 oxidation state reduces down the group, whilst stability of the +2 oxidation state increases down the group.
Describe how the stability of oxidation states changes down Group 5
In Group 5 (Group 15), stability of the +5 oxidation state reduces down the group, whilst stability of the +3 oxidation state increases down the group.
Describe the structure and bonding in Al2Cl6
Aluminium Hexachloride (Al2Cl6) is a donor-acceptor dimer. It is made up of two separate, identical molecules which are linked together by two dative bonds. Two atoms of chlorine share their lone pair of electrons with two atoms of aluminium to form the dative bonds.
Draw the structure of Al2Cl6
Describe the structure and bonding in NH3BF3
NH3BF3 is a donor-acceptor compound.
There is a dative coordinate bond formed between the nitrogen and boron atoms, where nitrogen supplies both the electrons for the covalent bond.
Describe the structure of cubic boron nitride
The cubic form of boron nitride consists of alternately linked boron and nitrogen atoms. The structure is a tetrahedral bond network which is similar to that of the carbon atoms in diamond. The lone pair of electrons on nitrogen are accepted by boron to give this giant 3D covalent lattice.