Which type of hybridization is exhibited by the oxygen atoms in the nitrate ion (NO_3^-)?

• A. sp^2
• B. sp^3
• C. sp
• D. none (oxygen atoms are not hybridized)

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the structure of the nitrate ion (NO_3^-). It consists of one nitrogen atom centrally bonded to three oxygen atoms, with resonance structures distributing the double bond among the oxygens.
2. Step 2: Recall that hybridization depends on the steric number, which is the number of atoms bonded plus the number of lone pairs on the atom in question. For oxygen in NO_3^-, consider its bonding and lone pairs.
3. Step 3: Each oxygen atom in NO_3^- is bonded to nitrogen with a single or partial double bond (due to resonance) and has two lone pairs of electrons. This means each oxygen has three regions of electron density (1 bond + 2 lone pairs).
4. Step 4: Using the steric number of 3, determine the hybridization of oxygen atoms. A steric number of 3 corresponds to sp^2 hybridization.
5. Step 5: Conclude that the oxygen atoms in the nitrate ion exhibit sp^2 hybridization because they have three electron regions around them, consistent with trigonal planar electron geometry.