Bonding: General Concepts – Study Notes

Bonding: General Concepts

Valence Electrons and Lewis Symbols

Valence electrons are the outermost electrons of an atom and are crucial in determining chemical bonding and reactivity. Lewis symbols are a simple way to represent the valence electrons of an element using dots around the chemical symbol.

• Valence Electrons: Electrons in the highest energy level (outer shell) of an atom.

• Lewis Symbol: The element's symbol surrounded by dots representing its valence electrons.

• Condensed Electron Configuration: Shorthand notation showing only the outermost electrons (e.g., Li: [He]2s1).

• Example: Carbon (C) has 4 valence electrons: [He]2s22p2, Lewis symbol: C with four dots.

Filling of electrons: The number of valence electrons corresponds to the group number for main group elements (e.g., Group 1: 1 valence electron, Group 17: 7 valence electrons).

Lewis Symbols and Group Number

The Lewis symbol for each element reflects its group number and electron configuration. This helps predict bonding behavior and the formation of ions.

Element	Electron Configuration	Lewis Symbol
Li	[He]2s1	Li•
Be	[He]2s2	Be••
B	[He]2s22p1	B•••
C	[He]2s22p2	C••••
N	[He]2s22p3	N•••••
O	[He]2s22p4	O••••••
F	[He]2s22p5	F•••••••
Ne	[He]2s22p6	Ne••••••••

Application: Lewis symbols are used to construct Lewis structures for molecules and ions, which help visualize bonding and predict molecular properties.

Additional info: For elements in Groups 1-2 and 13-18, the number of valence electrons equals the group number (for Groups 13-18, subtract 10).