Electron-Pair Geometries and Molecular Geometries

Vocabulary flashcards covering steric numbers, electron-pair geometries, molecular geometries, bond angles, and molecular examples based on VSEPR theory.

Lewis Structures

Two-dimensional molecular representations that are drawn flat on the page.

VSEPR Structures

Three-dimensional representations that use wedges and dashes, showing lone pairs only on the central atom.

Trigonal planar molecular geometry ($SN = 3$)

A molecular geometry resulting from 3 bonded atoms and 0 lone pairs, with a theoretical bond angle of $120^\circ$ (e.g., $CH_2O$).

Bent geometry ($SN = 3$)

An angular molecular geometry with a trigonal planar electron-pair geometry having 2 bonded atoms and 1 lone pair, with a theoretical bond angle of $<120^\circ$ (e.g., $SO_2$).

Tetrahedral molecular geometry

A molecular geometry resulting from 4 bonded atoms and 0 lone pairs with a tetrahedral electron-pair geometry, with a theoretical bond angle of $109.5^\circ$ (e.g., $CCl_4$).

Trigonal pyramidal geometry

A molecular geometry resulting from a tetrahedral electron-pair geometry ($SN = 4$) with 3 bonded atoms and 1 lone pair, having a theoretical bond angle of $<109.5^\circ$ (e.g., $NH_3$).

Bent geometry ($SN = 4$)

An angular molecular geometry resulting from a tetrahedral electron-pair geometry with 2 bonded atoms and 2 lone pairs, having a theoretical bond angle of $<109.5^\circ$ (e.g., $H_2O$).

Trigonal bipyramidal molecular geometry

A molecular geometry resulting from 5 bonded atoms and 0 lone pairs, featuring theoretical bond angles of $90^\circ$, $120^\circ$, and $180^\circ$ (e.g., $PF_3Cl_2$).

Seesaw geometry

A molecular geometry derived from a trigonal bipyramidal electron-pair geometry ($SN = 5$) with 4 bonded atoms and 1 lone pair, with theoretical bond angles of $<90^\circ$, $<120^\circ$, and $<180^\circ$ (e.g., $SCl_4$).

T-shaped geometry

A molecular geometry derived from a trigonal bipyramidal electron-pair geometry ($SN = 5$) with 3 bonded atoms and 2 lone pairs, with theoretical bond angles of $<90^\circ$ and $<180^\circ$ (e.g., $BrF_3$).

Linear geometry ($SN = 5$)

A molecular geometry derived from a trigonal bipyramidal electron-pair geometry with 2 bonded atoms and 3 lone pairs, with a theoretical bond angle of $180^\circ$ (e.g., $XeF_2$).

Octahedral molecular geometry

A molecular geometry resulting from an octahedral electron-pair geometry ($SN = 6$) with 6 bonded atoms and 0 lone pairs, having theoretical bond angles of $90^\circ$ and $180^\circ$ (e.g., $SF_6$).

Square pyramidal geometry

A molecular geometry derived from an octahedral electron-pair geometry ($SN = 6$) with 5 bonded atoms and 1 lone pair, having theoretical bond angles of $<90^\circ$ and $<180^\circ$ (e.g., $IF_5$).

Square planar geometry

A molecular geometry derived from an octahedral electron-pair geometry ($SN = 6$) with 4 bonded atoms and 2 lone pairs, having theoretical bond angles of $90^\circ$ and $180^\circ$ (e.g., $XeF_4$).