Stepwise Calculation and Geometry of NO₂, NO₂⁻, and NO₂⁺
Understanding the Hybridization Of NO2 is crucial for mastering chemical bonding and molecular structure questions in JEE Main Chemistry. Questions on hybridization not only test your basic concepts but also your ability to visualize molecular geometry and compare related ions like NO2+ and NO2-. The hybridization and shape of NO2 influence its bonding nature, resonance, and reaction mechanisms in various branches of chemistry.
Let’s break down the stepwise approach for calculating the hybridization of NO2, relate it to shape and molecular structure, and highlight key comparisons. This builds a strong foundation for application-based and numerical problems commonly seen in the JEE syllabus.
Hybridization Of NO2: Stepwise Calculation and Analysis
To determine NO2 hybridization, use the following stepwise strategy based on electron domain counting and VSEPR theory:
- Identify the central atom: Nitrogen (N).
- Count its valence electrons: Nitrogen has 5 valence electrons.
- Add electrons contributed by each oxygen: Two oxygens × 6 = 12.
- Total electrons: 5 (N) + 12 (O) = 17.
- NO2 is neutral: odd electron species (17 electrons), one unpaired electron.
- Draw Lewis structure: N is bonded to two O atoms, one double bond, one single, and one unpaired electron (radical), plus one lone pair.
- Calculate regions of electron density (bond pairs + lone pair): For N, 2 (from O bonds) + 1 (lone pair) = 3.
- With three regions, hybridization is sp2.
- Shape is bent (not linear), due to lone pair repulsion.
Quick tip: Steric number = (No. of σ bonds + No. of lone pairs on central atom). If steric number is 3, hybridization is sp2; if 2, it’s sp.
Geometry and Shape: NO2 vs NO2+ vs NO2-
The geometry of these nitrogen oxides is best understood through VSEPR theory and by comparing their structures:
| Species | Hybridization | Lone pairs on N | Shape | Bond Angle (approx.) |
|---|---|---|---|---|
| NO2 | sp2 | 1 | Bent (V-shaped) | ~134° |
| NO2+ | sp | 0 | Linear | 180° |
| NO2- | sp2 | 1 | Bent | ~115° |
Note that removal or addition of electrons changes both the hybridization and shape. Linear NO2+ (nitronium ion) regularly appears in MCQs relating hybridization to molecular geometry.
Lewis Structures and Resonance in Nitrogen Dioxide
NO2 and its ions have multiple resonance structures. In NO2, resonance distributes the odd electron between oxygen atoms, stabilizing the molecule. For NO2-, resonance makes both N-O bonds equivalent. This resonance is critical when discussing delocalized π-bonding and actual bond order.
- NO2: Delocalized unpaired electron, two resonance contributors.
- NO2+: No lone pairs on N, no resonance.
- NO2-: Lone pair present, two major resonance structures.
Understanding resonance helps explain fractional bond orders and deviations in bond angles from ideal geometry. Hybridization of NO2 is closely linked to resonance stabilization and effective electron delocalization.
Exam Applications: Hybridization of NO2 in JEE Questions
JEE Main frequently tests these concepts through:
- Calculating hybridization from Lewis structures of NO2, NO2+, NO2-.
- Matching species to geometry (linear, bent, planar).
- Error-spotting in electron counting or shape prediction.
- Comparing bond angles and hybridization between nitrogen oxides.
- Resonance’s effect on hybridization and shape choice in options.
For robust exam prep, always show your hybridization calculation steps. For example: NO2 (steric number 3 ⇒ sp2), NO2+ (steric number 2 ⇒ sp). Clearly connecting these steps in answers scores high in JEE Main Chemistry.
Summary Table: Key Data for Hybridization Of NO2 and Its Ions
| Species | Hybridization | Electron Domains | Lone Pairs (N) | Shape |
|---|---|---|---|---|
| NO2 | sp2 | 3 | 1 | Bent (V-shaped) |
| NO2- | sp2 | 3 | 1 | Bent |
| NO2+ | sp | 2 | 0 | Linear |
For rapid revision, remember: More lone pairs or extra electrons increase electron repulsions, reducing bond angles and distorting the geometry from ideal values.
- In NO2, the lone pair causes a bent structure, not trigonal planar.
- NO2+ is linear due to absence of any lone pair on nitrogen.
- Delocalization in NO2- leads to nearly equal N–O bond lengths.
Solidifying your approach to hybridization equips you to quickly tackle chemical bonding MCQs, resonance questions, and molecular structure applications in the JEE Main exam.
Explore Related Topics on Hybridization and Molecular Structures
- Hybridization of CO2—compare linear and bent geometries in dioxides.
- Hybridization of NO3-—spot differences with NO2 and resonance implications.
- Hybridization Chart with Examples—quickly reference hybridizations for exam revision.
- VSEPR Theory: Shapes of Molecules—master the rules for geometry prediction.
- Lewis Structures in Chemistry—practice drawing NO2, NO2-, and NO2+.
- Resonance Effect—see how resonance relates to hybridization in nitrogen oxides.
- Bond Angles and Shapes: MCQ Practice—test your understanding on structure-based problems.
- Hybridization of NH3—compare another lone pair nitrogen compound with NO2.
- Chemical Bonding and Molecular Structure—revisit fundamentals for clarity.
For JEE aspirants, mastering the hybridization of nitrogen dioxide and its related ions strengthens your grip on atomic structure, bonding theories, and application logic. Practice regularly and consult Vedantu's expert modules for deep conceptual clarity in Hybridization Of NO2 and allied topics.
FAQs on Hybridization and Molecular Structure of NO₂
1. What is the hybridization of NO2?
NO2 has sp2 hybridization at the nitrogen atom. This hybridization is crucial for understanding its bent molecular geometry, bonding, and lone pair arrangement.
Key features:
- Nitrogen atom in NO2 uses sp2 hybrid orbitals.
- One lone pair remains on nitrogen.
- The structure is bent (V-shaped) with an angle less than 120° due to lone pair repulsion.
2. How to determine the hybridization of NO2?
To determine the hybridization of NO2, count the regions of electron density (bonds and lone pairs) around nitrogen:
Step-by-step method:
- Draw the Lewis structure for NO2.
- Count sigma bonds (2 N–O) and lone pairs on N (1).
- Total = 3 steric number → corresponds to sp2 hybridization.
3. Is the shape of NO2 linear or bent?
NO2 is bent (V-shaped), not linear.
- This is due to one lone pair on nitrogen, which repels bond pairs and reduces the O-N-O bond angle to about 134° (less than 120°).
- VSEPR theory and sp2 hybridization both predict this bent shape.
4. What is the difference between NO2, NO2−, and NO2+ in terms of hybridization and shape?
NO2, NO2–, and NO2+ differ in hybridization, shape, and number of lone pairs:
- NO2: sp2 hybridization, 1 lone pair on N, bent shape.
- NO2–: sp2 hybridization, 2 lone pairs on N, also bent but with smaller bond angle.
- NO2+: sp hybridization, no lone pair, linear shape.
5. What is the geometry of NO2+?
NO2+ (Nitronium ion) has a linear geometry because the nitrogen is sp hybridized and has no lone pairs.
- Bond angle is 180°.
- Both N–O bonds are equivalent due to resonance.
6. How many lone pairs are present on nitrogen in NO2?
In NO2, the nitrogen atom has one lone pair of electrons.
- This lone pair influences the molecular geometry and reduces the O-N-O bond angle below 120°.
7. How does resonance affect the structure and hybridization of NO2?
Resonance in NO2 distributes double bond character equally between both N–O bonds and slightly modifies the bond order.
Effects include:
- Increased delocalization and bond equivalence.
- Hybridization calculation (sp2) still holds, as resonance structures do not affect the region count on nitrogen.
8. Can you explain the Lewis structure of NO2?
The Lewis structure of NO2 shows nitrogen double-bonded to one oxygen and single-bonded to the other, with an unpaired electron or lone pair remaining on nitrogen.
Drawing details:
- N is central, flanked by two O atoms.
- 1 double bond and 1 single bond with resonance between them.
- 1 lone pair on N (sometimes depicted as an unpaired electron).
9. What common mistakes do students make in finding NO2 hybridization?
Students often make errors calculating NO2 hybridization, mainly due to:
- Forgetting to count the lone pair on nitrogen.
- Confusing the shape (bent) with the electron geometry (trigonal planar).
- Ignoring the effect of resonance on bond order and length.
10. Why isn’t NO2 perfectly trigonal planar if it is sp2 hybridized?
NO2 is sp2 hybridized, which corresponds to a trigonal planar electron geometry. However, the presence of a lone pair on nitrogen exerts greater repulsion than bonding pairs, causing the actual shape to be bent and the bond angle to decrease below 120°.
11. How do you calculate the hybridization of NO2+?
To find hybridization of NO2+:
- Draw the Lewis structure – nitrogen forms two sigma bonds, no lone pairs.
- Steric number is 2 (2 bonds + 0 lone pairs).
- Steric number of 2 means sp hybridization, resulting in a linear shape.
12. Why is understanding hybridization of NO2 important for exams like JEE and NEET?
Knowing the hybridization of NO2 is essential because:
- It helps predict molecular geometry and bond angles, frequently asked in JEE, NEET and CBSE.
- It enables you to solve MCQs and numerical problems related to shape, resonance, and reaction mechanism.
- Such application-based questions assess concept clarity and error-spotting skills.
