Structure of the Periodic Table
- The periodic table is a tabular arrangement of chemical elements organized based on their increasing atomic number, from 1 to 118
- The periodic table is organized into horizontal rows called periods and vertical columns called groups
The Periodic Table
- Periods represent the principal energy shells of an element
- Groups are columns that share similar chemical properties due to the number of valence electrons
The Structure of the Beryllium Atom
The beryllium atom in the periodic table
- The periodic table is divided into four block types: s-block, p-block, d-block, and f-block
- s-block elements have only s electrons in their valence shell
- p-block elements have at least one p-electron in their valence shell
- d-block elements have at least one d-electron and one s-electron, but no p or f electrons in their outer shell (up to 5d)
- f-block elements have at least one f-electron and one s-electron, but not p or f electron in their outer shell
Blocks in the Periodic Table
s-block, p-block, d-block, and f-blocks in the Periodic Table
Electron Configurations
- The arrangement of electrons in the energy shells and subshells of an atom is described by its electron configuration
- The electron configuration of an element can be predicted by using the periodic table
- The image below shows how this can be done for the germanium atom:
Electron Configuration of the Germanium Atom
Deducing the electron configuration of germanium as 1s2, 2s2, 2p6, 3s2, 3d10, 4s2, 4p2
- Germanium is in the Group 4 (skipping the transition metals) and in Period 4
- Group 4 tells you that it has 4 valence electrons
- Period 4 tells you that it has the 4 valence electrons in the fourth shell
- Finally, germanium is in the second position of the p-block of the periodic table, therefore, two electrons must be in the p subshell