Electron Configurations & the Periodic Table
- The electron configuration of any element can be deduced from its position in the periodic table
- It is like an 'address' that tells you exactly where an element is found
- Using the element germanium as an example to illustrate how it works:
Interpreting the electronic configuration
Deducing the electron configuration of germanium
- Germanium is in p block, in group 4 (using the simplify numbering system) and the second element across in period 4
- Group 4 tells you there are four valence electrons and period 4 tells you the valence electrons are in the fourth shell
- The second position in p block tell you that two electrons are in the p subshell
- Similarly, you can deduce the position of an element in the periodic table from its electron configuration:
How to write electronic configuration
Deducing information from the electron configuration of chlorine
- Test your understanding in the following example:
Worked example
Element Z is in period 4 and group 5 of the periodic table. Which statement is correct?
A. Z has 5 occupied energy levels.
B. Z can form ions with 3– charge.
C. Z is a transition element.
D. Z has 4 valence electrons.
Answer:
- The correct option is B
- A group 5 element can form a 3– ion
- 5 occupied energy levels would place it in period 5, so A is incorrect
- Transition elements would not be found in group 5, so C is also incorrect
- 4 valence electrons would match an element in group 4, so D must be wrong