Groups of the Periodic Table

Understanding Groups

• Groups are the columns of the periodic table.
• Standard convention is to number them: 1 to 18.
• F block elements are not typically numbered in the main table.
• Elements in the same column/group have similar properties due to similar valence electron configurations.

Valence Electrons

• Valence electrons are in the outermost shell and are involved in chemical reactions.
• Some exceptions exist, particularly in the transition metals in the D block.

Group 1: Alkali Metals

• Excludes hydrogen (unique electron configuration goal: two like helium).
• Alkali metals have one valence electron.
• Highly reactive due to their tendency to lose one electron to achieve octet configuration.
• Properties: shiny, soft, often found in compounds due to reactivity.

Group 2: Alkaline Earth Metals

• Have two valence electrons.
• Reactive, but less so than alkali metals.
• React by losing two electrons to achieve octet.

Transition Metals: D Block

• Scandium's electron configuration example: [Ar] 3d¹ 4s².
• D block elements fill the D orbitals, impacting their chemical properties.

Group 14: Carbon Group

• Carbon example: [He] 2s² 2p².
• Four valence electrons lead to similar bonding patterns across the group.

Group 16: Oxygen Group

• Oxygen and sulfur have six valence electrons.
• Tend to gain two electrons to complete octet, leading to similar reactivity.

Group 17: Halogens

• Highly reactive due to having seven valence electrons.
• Tend to gain one electron, often react with alkali metals.

Group 18: Noble Gases

• Known for being non-reactive.
• Have full outer electron shells, achieving a stable configuration.

Summary

• The periodic table's structure allows prediction of element behavior based on group placement.
• Valence electrons play a key role in the chemical properties and reactivity of elements.