TOPIC: SHAPES OF MOLECULES PREAPARED TO :DR WAN NAZWANIE BINTI WAN ABDULLAH DR. PREPARED BY : NIK SOFEA AMIERA BINTI NIK REMELI (22303955) : SITI AISHAH BINTI AHMAD (22303768) C H H H O H H C H H H H
A ‘group‘of electrons is any number of electrons that occupies a localized region around an atom. A single bond,double bond,triple bond,lone pair,or single electron all count as a single group. O H H Valence-Shell Electron-Pair Repulsion Theory (VSEPR) This theory is important to predict the molecular shape from Lewis’s structure. In this theory. Valence-Shell Electron-Pair-Repulsion Theory (VSEPR) is a theory where each group valence electrons around a central atom is located as far as possible from others, to minimize repulsions. The electrons pairs that are lone and bonding electrons pair want to be as far away from each other as possible in molecules.
The electron-group arrangement is defined by both bonding and nonbonding electron group. The molecular shape is the threedimensional arrangement of nuclei joined by the bonding groups.This is defined only by the relative positions of the nuclei. What are differences between Electron-group Arrangement and Molecular Shape Molecular shape is classified using the designation AXmEn A = central atom X = surrounding atom E = nonbonding valence-electron group m and n are integers The electron-group arrangement is defined by both bonding and nonbonding electron group. key word key word
AX4 TYPES OF ELECTRON & MOLECULAR GEOMETRY Linear Trigonal planar Tetrahedral Trigonal bypiramidal Octahedral AX2E AX2E2 AX3E AX3E2 AX5E AX2E3 AX4E2 Bent AX AX3 2 AX5 AX6 AX4E Electron Geometry Molecular Geometry
EXAMPLE MOLECULE AX3 THE SHAPE OF MOLECULES Example THE SINGLE MOLECULAR SHAPE OF THE LINEAR ELECTRON-GROUP ARRANGEMENT LINEAR AX2 THERE ARE 2 ELECTRON PAIRS ARAOUND THE CENTRAL ATOM WHICH ALL BONDING PAIR ELECTRONS (AX2).THE MOLECULAR SHAPE IS LINEAR WITH THE BOND ANGLE OF 180 DEGREE. THE TWO MOLECULAR SHAPES OF TRIGONAL PLANAR ELECTRONGROUP ARRANGEMENT TRIGONAL PLANAR AX3 THERE ARE THREE ELECTRON PAIRS AROUND THE CENTRAL ATOM WHICH ALL BONDING PAIR ELECTRONS.THE MOLECULAR SHAPE IS TRIGONAL PLANAR WITH THE BOND ANGLE 120 DEGREE. THERE ARE THREE ELECTRON PAIRS AROUND THE CENTRAL ATOM WHICH ALL BONDING PAIR ELECTRONS.THE MOLECULAR SHAPE IS TRIGONAL PLANAR WITH THE BOND ANGLE 120 DEGREE. BENT (V SHAPE ) AX2E THERE ARE 3 ELECTRON PAIRS AROUND THE CENTRAL ATOM,WHICH ARE 2 BONDING PAIRS AND 1 LONE PAIRS (AX2E).THE MOLECULAR SHAPE IS V-SHAPE WITH THE BOND ANGLE LESS THAN 120 DEGREE. THERE ARE 3 ELECTRON PAIRS AROUND THE CENTRAL ATOM,WHICH ARE 2 BONDING PAIRS AND 1 LONE PAIRS (AX2E).THE MOLECULAR SHAPE IS V-SHAPE WITH THE BOND ANGLE LESS THAN 120 DEGREE. EXAMPLE MOLECULE AX2E
THE THREE MOLECULAR SHAPES OF TETRAHEDRAL ELECTRONGROUP ARRANGEMENT TETRAHEDRAL AX4 TRIGONAL PYRAMIDAL AX3E Example molecule AX3E Example molecule AX3E Explanation Example molecule of AX3 V-SHAPE AX2E2 Example molecule AX2E2 Example molecule AX2E2 EXAMPLE MOLECULE of AX5 EXAMPLE MOLECULE of AX5 EXAMPLE MOLECULE AX4E EXAMPLE MOLECULE AX4E EXAMPLE MOLECULE AX3E2 EXAMPLE MOLECULE AX3E2 EXAMPLE MOLECULE AX2E3 EXAMPLE MOLECULE AX2E3 There are 4 electrons pairs around the central atom which are all bonding pairs.The molecular shape is tetrahedral. There are 4 electrons pairs around the central atom which are all bonding pairs.The molecular shape is tetrahedral. FOUR MOLECULAR SHAPES OF THE TRIGONAL BIPYRAMIDAL ELECTRON-GROUP ARRANGEMENT There are 4 electrons pairs around the central atom,which are 3 lone pair and one lone pair.The bond angle is less than 109.5 degree There are 4 electrons pairs around the central atom,which are 3 lone pair and one lone pair.The bond angle is less than 109.5 degree THE ARE 4 ELECTRONS PAIRS Explanation AROUND THE CENTRAL ATOM WHICH ARE 2 BONDING PAIRS AND 1 LONE PAIR. THE MOLECULAR SHAPE IS BENT SHAPE WITH THE BOND ANGLE LESS THAN 120 DEGREE THE ARE 4 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ARE 2 BONDING PAIRS AND 1 LONE PAIR. THE MOLECULAR SHAPE IS BENT SHAPE WITH THE BOND ANGLE LESS THAN 120 DEGREE Explanation TRIGONAL BIPYRAMIDAL AX5 SEE-SAW AX4E T-SHAPE AX3E2 LINEAR AX2E3 THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ALL BONDING PAIRS .THE MOLECULAR SHAPE IS TRIGONAL BIPYRAMIDAL WITH BOND ANGLE IS 120 DEGREE AND 90 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ALL BONDING PAIRS .THE MOLECULAR SHAPE IS TRIGONAL BIPYRAMIDAL WITH BOND ANGLE IS 120 DEGREE AND 90 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM, WHICH ARE 4 BONDING PAIRS AND 1 LONE PAIR .THE MOLECULAR SHAPE IS SEESAW WITH EQUATORIAL ANGLE LESS THAN 120 DEGREE ANG THE AXIAL ANGLE IS LESS THAN 90 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM, WHICH ARE 4 BONDING PAIRS AND 1 LONE PAIR .THE MOLECULAR SHAPE IS SEESAW WITH EQUATORIAL ANGLE LESS THAN 120 DEGREE ANG THE AXIAL ANGLE IS LESS THAN 90 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ARE BONDING PAIRS AND 2 LONE PAIR .THE MOLECULAR SHAPE IS TSHAPED WITH THE BOND ANGLE LESS THAN 90 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ARE BONDING PAIRS AND 2 LONE PAIR .THE MOLECULAR SHAPE IS TSHAPED WITH THE BOND ANGLE LESS THAN 90 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH BONDING PAIRS AND 3 LONE PAIR. THE MOLECULAR SHAPE IS LINEAR WITH THE BOND ANGLE 0F 180 DEGREE. THERE ARE 5 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH BONDING PAIRS AND 3 LONE PAIR. THE MOLECULAR SHAPE IS LINEAR WITH THE BOND ANGLE 0F 180 DEGREE.
EXAMPLE MOLECULE AX6 THE THREE MOLECULAR SHAPES OF OCTAHEDRAL ELECTRON-GROUP ARRANGEMENT OCTAHEDRAL AX6 SQUARE PYRAMIDAL AX5E SQUARE PLANAR AX4E2 EXAMPLE MOLECULE AX5E EXAMPLE MOLECULE AX5E EXAMPLE MOLECULE AX4E2 EXAMPLE MOLECULE AX4E2 THERE ARE 6 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ALL BONDING PAIRS (AX6).THE MOLECULAR SHAPE IS OCTAHEDRAL WITH THE BOND ANGLE 90 DEGREE. THERE ARE 6 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ALL BONDING PAIRS (AX6).THE MOLECULAR SHAPE IS OCTAHEDRAL WITH THE BOND ANGLE 90 DEGREE. THERE ARE 6 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ARE 5 BONDING PAIRS AND 1 LONE PAIRS ELECTRONS (AX5E) .THE MOLECULAR SHAPE IS SQUARE PYRAMIDAL WITH THE BOND ANGLE OF LESS THAN 90 DEGREE. THERE ARE 6 ELECTRONS PAIRS AROUND THE CENTRAL ATOM WHICH ARE 5 BONDING PAIRS AND 1 LONE PAIRS ELECTRONS (AX5E) .THE MOLECULAR SHAPE IS SQUARE PYRAMIDAL WITH THE BOND ANGLE OF LESS THAN 90 DEGREE. TEHRE ARE 6 ELECTRONES PAIRS AROUND THE CENTRAL ATOM WHICH ARE BONDING PAIRS AND 2 LONE PAIR ELECTRONS.(AX4E2).THE MOLECULAR SHAPE IS SQUARE PLANAR WITH THE BOND ANGLE 90 DEGREE. TEHRE ARE 6 ELECTRONES PAIRS AROUND THE CENTRAL ATOM WHICH ARE BONDING PAIRS AND 2 LONE PAIR ELECTRONS.(AX4E2).THE MOLECULAR SHAPE IS SQUARE PLANAR WITH THE BOND ANGLE 90 DEGREE.