Atoms, Elements and Compounds
Core
• State the relative charges and approximate relative masses of protons, neutrons and
electrons
• Define proton number (atomic number) as the number of protons in the nucleus of an atom
• Define nucleon number (mass number) as the total number of protons and neutrons in the
nucleus of an atom
• Use proton number and the simple structure of atoms to explain the basis of the Periodic Table (see section 9), with special reference to the
elements of proton number 1 to 20
• Define isotopes as atoms of the same element which have the same proton number but a
different nucleon number
• State the two types of isotopes as being radioactive and non-radioactive
Core
• State one medical and one industrial use of radioactive isotopes
• Describe the build-up of electrons in ‘shells’ and understand the significance of the noble
gas electronic structures and of the outer shell electrons. (The ideas of the distribution
of electrons in s and p orbitals and in d-block elements are not required.)
Note: A copy of the Periodic Table, as shown in the Appendix, will be available in Papers 1, 2, 3 and 4.
Supplement
Chap#3 Atoms, Elements and ComoundsUnderstand that isotopes have the same properties because they have the same number
of electrons in their outer shell
3.2 Structure and bonding
3.2.1 Bonding: the structure of matter
Core
• Describe the differences between elements, mixtures and compounds, and between metals
and non-metals
• Describe an alloy, such as brass, as a mixture of a metal with other elements
3.2.2 Ions and ionic bonds
Core
• Describe the formation of ions by electron loss or gain
• Describe the formation of ionic bonds between elements from Groups I and VII
Supplement
• Describe the formation of ionic bonds between metallic and non-metallic elements
• Describe the lattice structure of ionic compounds as a regular arrangement of alternating positive and negative ions
3.2.3 Molecules and covalent bonds
Core
• Describe the formation of single covalent bonds in H2, Cl2, H2O, CH4, NH3 and HCl as the sharing of pairs of electrons leading to the noble gas
configuration
• Describe the differences in volatility, solubility and electrical conductivity between ionic and covalent compounds
Supplement
• Describe the electron arrangement in more complex covalent molecules such as N2, C2H4,
CH3OH and CO2
• Explain the differences in melting point and boiling point of ionic and covalent compounds in terms of attractive forces
3.2.4 Macromolecules
Core
• Describe the giant covalent structures of graphite and diamond
• Relate their structures to their uses, e.g. graphite as a lubricant and a conductor, and diamond in cutting tools
Supplement
• Describe the macromolecular structure of silicon(IV) oxide (silicon dioxide)
• Describe the similarity in properties between diamond and silicon(IV) oxide, related to their structures
3.2.5 Metallic bonding
Supplement
• Describe metallic bonding as a lattice of positive ions in a ‘sea of electrons’ and use this to describe the electrical conductivity and malleability of metals
