6.2. Electron Configuration and the Periodic Table http://www.ck12.org
6.2 Electron Configuration and the Periodic Table
Lesson Objectives
- Distinguish between core and valence electrons
- Understand the relationship between the number of orbitals in various energy sublevels and the length of the
periods in the periodic table. - Identify each block of the periodic table and be able to determine which block each element belongs to based
on its electron configuration. - Describe the relationship between outer electron configuration and group number. Be able to determine the
number of valence electrons for any element. - Locate the following groups of elements on the periodic table: alkali metals, alkaline earth metals, halogens,
noble gases, transition elements, lanthanides, and actinides.
Lesson Vocabulary
- valence electrons: The electrons that are in the highest occupied principal energy level (n).
- core electrons: The electrons that are closer to the nucleus and less available for interaction with other atoms.
- representative (main-group) elements: elements that have the s and p sublevels for a given principal energy
level. - alkali metals: The elements in Group 1 (lithium, sodium, potassium, rubidium, cesium, and francium).
- alkaline earth metals: The elements in Group 2 (beryllium, magnesium, calcium, strontium, barium, and
radium). - noble gases: The elements of Group 18 (helium, neon, argon, krypton, xenon, and radon).
- halogens: The elements of Group 17 (fluorine, chlorine, bromine, iodine, and astatine).
- transition elements: The elements that are found in Groups 3-12 on the periodic table.
- lanthanides: The 14 elements from cerium (atomic number 58) to lutetium (atomic number 71).
- actinides: The 14 elements from thorium (atomic number 90) to lawrencium (atomic number 103).
Check Your Understanding
- How to atoms form chemical bonds with one another? Are some elements more chemically reactive than
others?
Introduction
The development of the periodic table was largely based on elements that display similar chemical behavior. In the
modern table, these elements are found in vertical columns called groups. In this lesson, you will see how the form