Elements, compounds, atomic structure and isotopes

Learning objectives

Describe the differences between elements, compounds and mixtures

Describe the structure of an atom as a central nucleus of protons and neutrons surrounded by electrons in shells, and state the relative charges and relative masses of protons, neutrons and electrons

Define proton number (atomic number) and nucleon number (mass number), and use them to work out the numbers of protons, neutrons and electrons in atoms and ions from nuclide symbols such as ¹²₆C and ³⁵₁₇Cl⁻

Determine the electronic configuration of the first 20 elements (e.g. 2,8,1) and relate the group number to the number of outer-shell electrons and the period number to the number of occupied shells

Define isotopes as atoms of the same element with different numbers of neutrons and, at Extended, explain why isotopes of an element share the same chemical properties

Calculate the relative atomic mass of an element from the relative masses and abundances of its isotopes (Extended)