The periodic table and periodicity
Describe the arrangement of the periodic table.
The periodic table arranges elements in order of increasing atomic (proton) number. The table is further arranged in periods showing repeating trends in physical and chemical properties and in groups having similar chemical properties. The periodic table has been extended through discovery and confirmation of new elements.
You should also be aware of the history of the development of the periodic table and how it illustrates some important Working scientifically principles. For example, Mendeleev used the patterns in the properties of the known elements to predict the properties of undiscovered elements; when these elements were discovered, the predictions could be tested against the observed properties.
Describe how elements are classified into s-, p- and d-blocks.
Give the definition of the first ionization energy.
The removal of 1 mol of electrons from 1 mol of gaseous atoms.
Explain the trend in first ionisation energies across Periods 2 and 3, and down a group, in terms of attraction, nuclear charge and atomic radius.
Explanation to include the small decreases as a result of s- and p-sub-shell energies (e.g. between Be and B) and p-orbital repulsion (e.g. between N and O).
Describe the prediction from successive ionisation energies of the number of electrons in each shell of an atom and the group of an element.
Define Metallic bonding.
Metallic bonding is the strong electrostatic attraction between cations and delocalised electrons, forming a giant metallic lattice structure.
Describe the structure of solid giant covalent lattices.
Solid giant covalent lattices of carbon (diamond, graphite and graphene) and silicon are networks of atoms bonded by strong covalent bonds. Use of ideas about bonding to explain the strength and conductive properties of graphene, and its potential applications and benefits.
Give the physical properties of giant metallic and giant covalent lattices, including melting and boiling points, solubility and electrical conductivity in terms of structure and bonding.
Explanations should be in terms of the types of particle present in a lattice, the relative strength of forces and bonds, and the mobility of the particles involved, as appropriate.
Describe the differences between a giant covalent lattice and the simple molecular lattice formed by simple covalently-bonded molecules in the solid state.
Explain the variation in melting points across Periods 2 and 3 in terms of structure and bonding.
Trend in structure from giant metallic to giant covalent to simple molecular lattice.