Draw the Lewis structure for the hydronium ion, H₃O⁺.

Draw the Lewis structure for the hydronium ion, H₃O⁺.

The Correct Answer and Explanation is:

The hydronium ion, ( H_3O^+ ), is a polyatomic ion formed when a proton (H⁺) is added to a water molecule (H₂O). Here’s how to draw its Lewis structure and a detailed explanation:

Steps to Draw the Lewis Structure for ( H_3O^+ ):

1. Determine the Total Number of Valence Electrons:

• Oxygen (O) is in group 16 of the periodic table, so it has 6 valence electrons.
• Each hydrogen (H) atom contributes 1 valence electron, and since there are 3 hydrogens, this gives 3 electrons.
• The positive charge ( + ) means the ion has lost one electron, so we subtract 1 from the total count.
• The total number of valence electrons is:
  [
  6 (\text{from O}) + 3 (\text{from H}) – 1 (\text{for the + charge}) = 8 \text{ valence electrons}.
  ]

1. Determine the Central Atom:

• Oxygen is the most electronegative atom and will be the central atom, with hydrogens attached to it.

1. Connect the Atoms:

• Oxygen (O) will be at the center, and the three hydrogen (H) atoms will be bonded to it. Each bond between oxygen and hydrogen is a single bond, using two electrons per bond.

1. Distribute the Electrons:

• Each O-H bond uses two electrons, so 3 bonds will use 6 electrons in total (3 × 2 electrons).
• The remaining 2 electrons will be placed as a lone pair on the oxygen atom.

1. Consider the Charge:

• Since the hydronium ion has a ( + ) charge, we need to place the positive charge on the oxygen atom. This occurs because oxygen has a lone pair, but it shares its electron density with hydrogen atoms in a way that leaves it electron-deficient.

Final Lewis Structure:

• Oxygen (O) is at the center with three single bonds to hydrogen atoms.
• Oxygen also has one lone pair of electrons.
• The hydronium ion has a positive charge, which is typically shown near the oxygen atom.

   H
   |
H—O—H
   |
   H

Explanation:

The hydronium ion consists of a central oxygen atom bonded to three hydrogen atoms. In this ion, oxygen forms single bonds with each hydrogen, utilizing 6 electrons for these bonds. The remaining 2 electrons on oxygen form a lone pair. The positive charge indicates that one electron is lost, which is often represented as being removed from the oxygen atom. This electron loss contributes to the creation of a positively charged ion. The structure ensures that oxygen satisfies the octet rule, while each hydrogen atom achieves a duet rule (2 electrons in its valence shell). The overall structure is stable due to the formation of covalent bonds and the appropriate distribution of electrons.