CLASS 7 · LEARNING KNOWLEDGE
Periodic table as an ordering system – basic principles
How it works
The periodic table of the elements (PSE) orders the chemical elements by increasing atomic number (number of protons in the atomic nucleus). It is divided into periods (rows) and groups (columns). Elements of the same main group have similar chemical properties because they have the same number of outer electrons. The periods indicate the number of occupied electron shells. The PSE helps to recognize the properties, reactivity, and relationships of the elements.
Note
In the periodic table, the elements are arranged by increasing atomic number. For the main groups, the following applies: Elements of the same main group have the same number of outer electrons and therefore similar chemical properties. The periods indicate the number of occupied electron shells.
In the periodic table, the elements are arranged by increasing atomic number. For the main groups, the following applies: Elements of the same main group have the same number of outer electrons and therefore similar chemical properties. The periods indicate the number of occupied electron shells.
An example
What common feature do all elements of a main group have in the periodic table?
All elements of a main group have the same number of outer electrons. Therefore, they often show similar chemical properties.
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50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Chemistry. The topic assignment may vary by federal state.