Question

An oxygen atom can bond to a hydrogen iodide molecule to give HIO. Draw the electron dot formula for HIO and label a coordinate covalent bond.

Short answer

HIO's structure shows a coordinate covalent bond from oxygen to iodine.

Step-by-step solution

Understand the Atoms Involved

In the molecule HIO, we have three atoms involved: hydrogen (H), iodine (I), and oxygen (O). Hydrogen has 1 electron, iodine has 7 valence electrons, and oxygen has 6 valence electrons.

Determine Valence Electrons

Calculate the total number of valence electrons in HIO. Hydrogen contributes 1 electron, iodine contributes 7 electrons, and oxygen contributes 6 electrons. The total number of valence electrons is thus 1 + 7 + 6 = 14 electrons.

Draw the Basic Structure

Draw the skeletal structure of HIO with oxygen in the center bonded to hydrogen and iodine. Initially, place single bonds between O and H, and O and I. The initial arrangement is H-O-I.

Allocate Electrons to Bonds

Each single bond in H-O-I uses 2 electrons. The bonds H-O and O-I each use 2 electrons. Subtract the 4 electrons used in bonds from the total of 14, leaving 10 electrons remaining.

Complete the Octet Rule

Distribute the remaining electrons to satisfy the octet rule. Start by placing remaining electrons as lone pairs on iodine and oxygen. Iodine needs three pairs (6 electrons), and oxygen needs two pairs (4 electrons), fulfilling the octet rule for iodine and competing oxygen's octet from electrons in the molecule.

Identify Coordinate Covalent Bond

In this configuration, oxygen provides a pair of electrons to form the bond with iodine, fulfilling iodine's requirement to have full outer shells. This type of bonding where both shared electrons come from the same atom is known as a coordinate covalent bond.

Key concepts

Electron Dot Structure

The electron dot structure, also known as the Lewis Dot structure, is a schematic representation used to show the valence electrons of atoms within a molecule. This representation aids in the understanding of the arrangement of electrons around atoms and helps visualize how atoms bond and form molecules. For drawing the electron dot structure:

• Each dot represents a valence electron.
• Elements are symbolized by their chemical symbols.
• Dots are placed around the symbol to indicate the number of valence electrons.

In a molecule like HIO, hydrogen contributes 1 electron, iodine contributes 7, and oxygen contributes 6, which are added as dots around their respective elemental symbols. Bonds between atoms are depicted by lines, each representing a pair of shared valence electrons. This visual framework helps in further constructing and understanding the bonding within the molecule.

Valence Electrons

Valence electrons are the outermost electrons of an atom and are crucial in determining how atoms bond with one another. They play a vital role in chemical bonding since they are the electrons involved in forming bonds.

• For hydrogen, there are 1 valence electron.
• Iodine possesses 7 valence electrons.
• Oxygen has 6 valence electrons.

The ability of an atom to bond depends on its valence electrons, which participate in the formation of chemical bonds by being shared, gained, or lost. In the HIO molecule, the distribution of these valence electrons allows for the formation of stable bonds and the satisfaction of the octet rule, especially for atoms like oxygen and iodine which follow this rule closely due to their electron configuration.

Coordinate Covalent Bond

A coordinate covalent bond, also known as a dative bond, occurs when one atom provides both electrons needed for the formation of a covalent bond. This type of bond is particularly interesting because unlike typical covalent bonds, which involve the sharing of electrons from both atoms, here only one atom donates a pair of electrons while the other atom accepts them fully to complete its electronic configuration. In the molecule HIO:

• Oxygen supplies a pair of electrons to iodine to form this bond.
• This happens when iodine does not have enough electrons to fulfill the octet rule independently.
• Oxygen acts as a donor, providing the electrons which iodine then shares in their bond.

This concept helps in understanding unique bonding situations where electron-sharing does not occur evenly, yet the atoms involved still achieve a stable configuration through such interactions.