Read the two statements below about the compounds H2Y, Li2Y, HZ and
KZ and then answer the questions that follow:
A non-metal element which lies in the third row of the Periodic Table
forms a gaseous compound H2Y with hydrogen and the compound
Li2Y with lithium, which has a solid crystalline structure and a high
melting point (greater than 900 °C).
• A non-metal element which lies in the fourth row of the Periodic Table
forms a gaseous compound HZ with hydrogen and the compound KZ
with potassium, which has a solid crystalline structure and a high
melting point (greater than 700 °C)
(i)Identify to which Group of the Periodic Table the elements Y and Z
belong and hence write down the name and chemical symbol of Y and
Z. Give brief reasoning on how you arrived at your answers, including
the likely valency of Y and Z in the compounds given.
(ii) What type of bonding is involved in compounds Li2Y and KZ? Give
your reasoning.
(iii) State two different conditions under which you would expect
compounds Li2Y and KZ to conduct electricity. Explain your answer
in terms of the type of bonding found in the compounds.
1 answer