Valence Electrons and Lewis Dot

Valence electrons

Electrons located in the outermost electron shell, least tightly held by the atom, and participate in bond formation and reactivity.

Group number

Determines the number of valence electrons an element has, with Na in group 1 having one valence electron and Cl in group 7 having 7 valence electrons.

Octet rule

Atoms will form bonds with their valence electrons to achieve a full outer shell of eight electrons, mimicking the electron configuration of noble gases.

Lewis Dot

A representation of the valence electrons in an atom, used in the Lewis Theory to draw Lewis Structures for molecules.

Electronegativity

The tendency of an atom to attract shared electrons in a chemical bond, decreasing down a group and increasing from left to right across a period.

Lewis Structures

A procedure for drawing molecular structures, involving steps like counting valence electrons, fulfilling the octet rule, determining the number of bonds, choosing a central atom, and completing octets with lone pairs.

Formal Charges

compares the number of electrons around a "neutral atom" (an atom not in a molecule) versus the number of electrons around an atom in a molecule

Formal charges formula

(# of valence electrons in free atom) − (# of lone-pair electrons) − (1/2 # of bond pair electrons)