Periodic table

Nature of science:

Obtain evidence for scientific theories by making and testing predictions based on them—scientists organize subjects based on structure and function; the periodic table is a key example of this. Early models of the periodic table from Mendeleev, and later Moseley, allowed for the prediction of properties of elements that had not yet been discovered. (1.9)

• The periodic table is arranged into four blocks associated with the four sub- levels—s, p, d, and f.
• The periodic table consists of groups (vertical columns) and periods (horizontal rows).
• The period number (n) is the outer energy level that is occupied by electrons.
• The number of the principal energy level and the number of the valence electrons in an atom can be deduced from its position on the periodic table.
• The periodic table shows the positions of metals, non-metals and metalloids.

Applications and skills:

• Deduction of the electron configuration of an atom from the element’s position on the periodic table, and vice versa.

Guidance:

• The terms alkali metals, halogens, noble gases, transition metals, lanthanoids and actinoids should be known.
• The group numbering scheme from group 1 to group 18, as recommended by IUPAC, should be used.

• The development of the periodic table took many years and involved scientists from different countries building upon the foundations of each other’s work and ideas.

Theory of knowledge:

• What role did inductive and deductive reasoning play in the development of the periodic table? What role does inductive and deductive reasoning have in science in general?

Utilization:

• Other scientific subjects also use the periodic table to understand the structure and reactivity of elements as it applies to their own disciplines.
• Syllabus and cross-curricular links:
• Topic 2.2—electron configuration

Aims:

• Aim 3: Apply the organization of the periodic table to understand general trends in properties.
• Aim 4: Be able to analyse data to explain the organization of the elements.
• Aim 6: Be able to recognize physical samples or images of common elements.