Chemistry 3.2.1 Flashcards
What structure do group 1, 2 and 3 metals have?
Metallic.
What structure does Si have?
Macromolecular.
What structure do P4, S8, Cl2 and Ar have?
Simple molecular.
Which structures have the lowest, medium and highest mp and bps.
Simple molecular structures have the lowest bp and mp.. Metallic structures have the medium bp and mp. Macromolecular structures have the highest bp and mp.
Why are metallic bonds hard to break?
Attraction with the positive ions and delocalised electrons (which increase in number across the period).
How many bonds does Si have and what is its structure?
4 bonds in a giant tetraphedral structure.
Why is the melting point of Si high?
Silicon atoms are held tightly by strong covalent bonds which need lots of energy to be broken.
Why do simple molecular structured elements have low mp and bps?
Weak Van der Waals forces between molecules which lose strength as the size of the molecule decrease.
What is the trend in atomic radius down the group?
Increases with constant shilding.
What is the trend in ionisation energy down a group?
Decreases due to increase in atomic radius and increase in the number of filled principle energy levels.
What is the trend in ionisation energy across a period?
Increase due to increase in number of protons in the nucleus. Electrons are held more tightly due to contant shielding so they’re harder to ionise.
What are the exceptions to the trends in ionisation energy?
Mg IE > Al IE as the electron is removed from a lower principle energy level. P IE > S IE as the electrons in the p principle energy level of S are paired meaning there’s more repulsion.
