Question

Using the VSEPR theory, predict the molecular structure of each of the following polyatomic ions. a. chlorate ion b. chlorite ion c. perchlorate ion

Short answer

The molecular geometries of the polyatomic ions using VSEPR theory are: a. Chlorate ion (ClO3^-): T-shaped b. Chlorite ion (ClO2^-): Linear c. Perchlorate ion (ClO4^-): Square planar

Step-by-step solution

VSEPR theory states that the molecular structure of a molecule can be predicted based on the number of bonding electron pairs and lone pairs on the central atom. The bonding electron pairs and lone pairs will repel each other, and the shape of the molecule will be the one that minimizes the repulsion between these regions of high electron density. #Step 2: Write the formula of each ion#

a. Chlorate ion: ClO3^- b. Chlorite ion: ClO2^- c. Perchlorate ion: ClO4^- #Step 3: Draw the Lewis structure for each ion#

For each ion, we will need to find the total number of valence electrons and distribute them to satisfy the octet rule: a. Chlorate ion: Cl has 7 valence electrons + 3 × 6 valence electrons for each O + 1 extra electron for the negative charge = 26 electrons Lewis structure for the chlorate ion: Cl (central atom) is singly bonded to three O atoms, with one O also having a double bond. Each O atom has 6 electrons around it, and Cl has 3 lone pairs. b. Chlorite ion: Cl has 7 valence electrons + 2 × 6 valence electrons for each O + 1 extra electron for the negative charge = 20 electrons Lewis structure for the chlorite ion: Cl (central atom) is singly bonded to two O atoms, with one O having a double bond. Each O atom has 6 electrons around it, and Cl has 4 lone pairs. c. Perchlorate ion: Cl has 7 valence electrons + 4 × 6 valence electrons for each O + 1 extra electron for the negative charge = 32 electrons Lewis structure for the perchlorate ion: Cl (central atom) is singly bonded to four O atoms, with each O having a double bond. Each O atom has 6 electrons around it, and Cl has 2 lone pairs. #Step 4: Apply VSEPR theory to predict molecular geometries#

a. Chlorate ion: The central Cl atom is surrounded by 3 bonding electron pairs and 3 lone pairs (6 electron groups in total). Therefore, an octahedral electron group geometry is expected. Since Cl has 3 bond pairs and 3 lone pairs around it, it has a T-shaped molecular geometry. b. Chlorite ion: The central Cl atom is surrounded by 2 bonding electron pairs and 4 lone pairs (6 electron groups in total). Therefore, an octahedral electron group geometry is expected as well. Since Cl has 2 bond pairs and 4 lone pairs around it, it has a linear molecular geometry. c. Perchlorate ion: The central Cl atom is surrounded by 4 bonding electron pairs and 2 lone pairs (6 electron groups in total). Therefore, an octahedral electron group geometry is also expected. Since Cl has 4 bond pairs and 2 lone pairs around it, it has a square planar molecular geometry.