Describe how Mendeleev arranged the elements, known at that time, in a periodic table by using properties of these elements and their compounds

Describe how Mendeleev used his table to predict the existence and properties of some elements not then discovered

Explain that Mendeleev thought he had arranged elements in order of increasing relative atomic mass but this was not always true because of the relative abundance of isotopes of some pairs of elements in the periodic table

Explain the meaning of atomic number of an element in terms of position in the periodic table and number of protons in the nucleus

Describe that in the periodic table

a) elements are arranged in order of increasing atomic number, in rows called periods
b) elements with similar properties are placed in the same vertical columns called groups

Identify elements as metals or non-metals according to their position in the periodic table, explaining this division in terms of the atomic structures of the elements

Predict the electronic configurations of the first 20 elements in the periodic table as diagrams and in the form, for example 2.8.1

Explain how the electronic configuration of an element is related to its position in the periodic table