Valence Electrons, Bohr Models, and Lewis Dot Structures

Vocabulary practice flashcards generated from chemistry lecture notes covering valence electrons, periodic table groups, the octet rule, Bohr models, and Lewis dot structures.

Valence Electrons

The electrons located in the outermost shell of an element's orbitals that are responsible for an atom's bonding behavior.

Octet Rule

The tendency for atoms to want $8$ valence electrons in order to achieve greater stability (derived from the Greek root [oct] meaning $8$).

Group 1 (Alkali Metals)

The least stable group on the periodic table because its elements contain only $1$ valence electron.

Group 18 (The Noble Gases)

The most stable group on the periodic table because its elements have a full outer shell of $8$ valence electrons, making them inert (unreactive).

Helium (Octet Exception)

The only Noble Gas that does not have $8$ valence electrons; it has only $2$ electrons total, which completely fills its first outer orbital shell.

Bohr Model

A simplified visual representation of an atom that uses concentric rings around a nucleus to show orbitals, useful for identifying valence electrons in the first $20$ elements.

Bohr Model Electron Ring Capacities

The maximum electron capacities for orbital rings in the first $20$ elements: 1st ring holds $2 e^-$; 2nd ring holds $8 e^-$; 3rd ring holds $8 e^-$; 4th ring holds $2 e^-$.

Lewis Dot Structure

A visual representation of an atom's valence electrons using dots placed around the four sides of its chemical symbol.

Transition Metals (Valence Electrons)

Elements located in the middle block of the periodic table that typically have $2$ to $3$ valence electrons.

Periodic Table Groups ('A' Notation)

The system where vertical columns labeled with an 'A' specify the number of valence electrons (e.g., Boron in Group 3A has $3$ valence electrons, not $13$).

Sodium Bohr Model Example

A Bohr diagram showing Sodium ($\text{Na}$) with a total of $11$ electrons distributed across $3$ orbital rings and $1$ valence electron in its outermost shell.

Potassium Bohr Model Example

A Bohr diagram showing Potassium ($\text{K}$) with $19$ total electrons distributed across $4$ rings following the pattern $2$, $8$, $8$, $1$.

Oxygen Lewis Dot Structure Example

A Lewis dot diagram showing Oxygen ($\text{O}$) with its $6$ valence electrons drawn as dots around the sides of its chemical symbol.