Chemical bonding is a critical topic in NEET, encompassing ideas like ionic, covalent, and metal bonds. Understanding bond formation, polarity, and molecular geometry is crucial for predicting molecular conduct and reactivity. NEET questions regularly consciousness on bond strengths, resonance systems, and the function of hybridization in molecular shapes. Mastery of this concern facilitates students address complex issues in organic and inorganic chemistry, making it critical for success in the exam and future studies within the medical discipline.
Introduction to Chemical Bonding
Chemical bonding is a fundamental concept in chemistry that explains how atoms have interaction to shape molecules. Understanding the kinds of chemical bonds—ionic, covalent, and steel—is critical for NEET aspirants, as these principles underpin many biological and physical techniques. Questions associated with chemical bonding in the NEET exam regularly assess students’ comprehension of molecular structures, bond energies, and the conduct of compounds in diverse environments. Mastery of these topics now not best helps in solving direct questions however also complements problem-solving abilties for associated topics like organic chemistry and biochemistry. Therefore, an intensive hold close of chemical bonding is vital for reaching achievement in the NEET exam and for destiny research in the field of medication and fitness sciences.
Importance in NEET
Chemical bonding is an important subject matter in the NEET syllabus for several reasons:
- Foundation for Chemistry: It provides the fundamental concepts that are essential for understanding different subjects in chemistry, including molecular shape, chemical reactions, and properties of substances.
- Predicting Molecular Structure: Chemical bonding helps predict the shape and arrangement of atoms in molecules, which is crucial for understanding their properties and reactivity.
- Explaining Chemical Properties: Chemical bonding explains why different materials have specific properties, including boiling points, melting points, and solubility.
- Understanding Chemical Reactions: Chemical bonding is critical for understanding how chemical reactions occur and why certain reactions are more likely to take place than others.
Download: Chemical Bonding
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|---|---|
| Chemical Bonding NEET Questions with Answer | Click Here |
Types of Chemical Bonds
| Type of Bond | Definition | Example |
|---|---|---|
| Ionic Bond | Formed between a metal and a nonmetal, involving the transfer of electrons. | NaCl (sodium chloride) |
| Covalent Bond | Formed between two nonmetals, involving the sharing of electrons. | H₂ (hydrogen molecule) |
| Metallic Bond | Formed between metal atoms, involving the sharing of valence electrons among all atoms in the metal. | Cu (copper metal) |
| Coordinate (Dative) Bond | A type of covalent bond where one atom donates both electrons to the bond. | NH₄⁺ (ammonium ion) |
Properties of Ionic Compounds
| Property | Explanation | Example |
|---|---|---|
| Melting and Boiling Points | Generally high because of the sturdy electrostatic appeal among ions. | NaCl has a high melting point of 801 °C. |
| Solubility | Many ionic compounds are soluble in water due to the formation of ion-dipole interactions. | NaCl is soluble in water. |
| Electrical Conductivity | Conduct energy whilst molten or dissolved in water due to the presence of unfastened ions. | Molten NaCl conducts power. |
Properties of Covalent Compounds
| Property | Explanation | Example |
|---|---|---|
| Molecular Geometry | The three-dimensional association of atoms in a molecule, decided through VSEPR principle. | Water molecule (H₂O) has a bent form. |
| Polarity | The distribution of electron density in a molecule, main to partial advantageous and negative prices. | HCl molecule is polar due to the distinction in electronegativity among hydrogen and chlorine. |
| Intermolecular Forces | Weak forces between molecules, consisting of London dispersion forces, dipole-dipole forces, and hydrogen bonding. | Water molecules are interested in every different through hydrogen bonding. |
Valence Bond Theory
Concept of Hybridization
Hybridization is a theoretical concept in valence bond theory that explains the formation of covalent bonds among atoms. It entails the mixing of atomic orbitals to form new hybrid orbitals that are more suitable for bonding. The number and type of hybrid orbitals formed depend upon the number of sigma bonds and lone pairs around the central atom.
Types of Hybridization
There are different types of hybridization based on the number and arrangement of hybrid orbitals:
- sp hybridization: One s orbital and one p orbital combine to form sp hybrid orbitals. This type of hybridization is found in molecules with sigma bonds and no lone pairs around the central atom, such as BeCl2 and CO2.
- sp2 hybridization: One s orbital and two p orbitals combine to form three sp2 hybrid orbitals. This kind of hybridization is observed in molecules with three sigma bonds and one lone pair around the central atom, including BF3 and C2H4.
- sp3 hybridization: One s orbital and three p orbitals combine to form four sp3 hybrid orbitals. This type of hybridization is found in molecules with four sigma bonds and no lone pairs around the central atom, such as CH4 and NH3.
- d2sp3 hybridization: One d orbital, two s orbitals, and three p orbitals combine to form six d2sp3 hybrid orbitals. This type of hybridization is observed in molecules with six sigma bonds and no lone pairs around the central atom, such as SF6 and PCl5.
Applications of Valence Bond Theory
- Valence bond theory can be used to explain the structure and bonding of molecules.
- It can help to predict the shape and polarity of molecules.
- It can also be used to understand the reactivity of molecules.
Molecular Orbital Theory
Molecular Orbital Theory (MOT) is a quantum mechanical model that describes the bonding among atoms in molecules. It proposes that when atoms combine to shape a molecule, their atomic orbitals overlap to form new molecular orbitals.
Formation of Molecular Orbitals
- Linear Combination of Atomic Orbitals (LCAO): This method assumes that the molecular orbitals are formed by combining the atomic orbitals of the character atoms.
- Constructive Interference: When atomic orbitals overlap in segment, they integrate to shape bonding molecular orbitals (BMOs). These orbitals have lower energy than the atomic orbitals.
- Destructive Interference: When atomic orbitals overlap out of segment, they combine to shape antibonding molecular orbitals (ABMOs). These orbitals have higher strength than the atomic orbitals.
Bonding and Antibonding Orbitals
- Bonding Molecular Orbitals (BMOs): These orbitals have higher electron density between the nuclei, leading to a strong appeal among the atoms.
- Antibonding Molecular Orbitals (ABMOs): These orbitals have a node between the nuclei, leading to repulsion among the atoms.
Bond Order
The bond order is calculated as (wide variety of electrons in bonding orbitals – wide variety of electrons in antibonding orbitals) / 2. A bond order of 0 indicates no bond, 1 suggests a single bond, 2 suggests a double bond, and so on.
Molecular Orbital Diagrams
Molecular orbital diagrams are used to visualize the power degrees of molecular orbitals and the distribution of electrons in a molecule.
Filling Molecular Orbitals
Electrons are crammed into the molecular orbitals in step with the Aufbau principle, Hund’s rule, and Pauli’s exclusion precept.
HOMO and LUMO
The highest occupied molecular orbital (HOMO) and the bottom unoccupied molecular orbital (LUMO) are crucial in determining the reactivity of a molecule.
Factors Affecting Chemical Bonding
1. Electronegativity
Definition: Electronegativity is the ability of an atom to draw electrons in the direction of itself in a covalent bond.
Impact on Bonding:
- Ionic Bonding: A big difference in electronegativity among two atoms leads to ionic bonding, wherein one atom donates an electron to the opposite.
- Covalent Bonding: A smaller distinction in electronegativity ends in covalent bonding, wherein atoms percentage electrons.
- Polar Covalent Bonding: A slight difference in electronegativity results in polar covalent bonding, where the shared electrons aren’t equally dispensed among the atoms.
2. Atomic Size
Definition: Atomic size refers back to the common distance among the nucleus and the outermost electrons of an atom.
Impact on Bonding:
- Ionic Bonding: Smaller atoms are more likely to shape ionic bonds because of their stronger enchantment for electrons.
- Covalent Bonding: Larger atoms tend to form weaker covalent bonds due to the extended distance between their nuclei and the shared electrons.
3. Ionization Energy
Definition: Ionization strength is the energy required to dispose of an electron from an atom.
Impact on Bonding:
- Ionic Bonding: Atoms with low ionization energies are more likely to lose electrons and shape cations, at the same time as atoms with high ionization energies are much more likely to advantage electrons and shape anions.
- Covalent Bonding: Atoms with similar ionization energies are much more likely to form covalent bonds.
Common Chemical Bonding Questions for NEET
Multiple Choice Questions
| Question | Answer | Explanation |
|---|---|---|
| Which type of bond is formed between two atoms with a large difference in electronegativity? | Ionic bond | The atom with higher electronegativity attracts the electron(s) from the other atom. |
| Which type of bond is formed between two atoms with a small difference in electronegativity? | Covalent bond | The atoms share electrons to achieve a stable electron configuration. |
| Which type of bond is formed between two identical atoms? | Nonpolar covalent bond | The electrons are shared equally between the atoms due to their equal electronegativity. |
| Which molecule has a polar covalent bond? | HCl | The difference in electronegativity between hydrogen and chlorine creates a polar covalent bond. |
| Which molecule has a nonpolar covalent bond? | Cl2 | The two chlorine atoms have the same electronegativity, resulting in a nonpolar covalent bond. |
| Which theory explains the formation of covalent bonds using overlapping atomic orbitals? | Valence Bond Theory | This theory proposes that bonds form when atomic orbitals overlap. |
| Which theory explains the formation of molecular orbitals using linear combinations of atomic orbitals? | Molecular Orbital Theory | This theory proposes that molecular orbitals are formed by combining atomic orbitals. |
| Which type of hybridization occurs in methane (CH4)? | sp3 | Carbon has four sigma bonds, requiring four hybrid orbitals. |
| Which type of hybridization occurs in ethylene (C2H4)? | sp2 | Each carbon has three sigma bonds and one pi bond, requiring three hybrid orbitals. |
| Which type of hybridization occurs in acetylene (C2H2)? | sp | Each carbon has two sigma bonds and two pi bonds, requiring two hybrid orbitals. |
Assertion and Reason Type Questions
| Assertion | Reason |
|---|---|
| Ionic compounds have high melting points. | Ionic bonds are strong electrostatic attractions between ions. |
| Covalent compounds have low melting points. | Covalent bonds are weaker than ionic bonds. |
| Polar covalent molecules are attracted to each other. | Polar covalent molecules have a permanent dipole moment. |
| Nonpolar covalent molecules are not attracted to each other. | Nonpolar covalent molecules do not have a permanent dipole moment. |
| Water molecules are attracted to each other through hydrogen bonding. | Hydrogen bonding is a special type of dipole-dipole interaction. |
Numerical Problems
| Problem | Solution |
|---|---|
| Calculate the bond order of O2. | Bond order = (number of bonding electrons – number of antibonding electrons) / 2 = (10 – 6) / 2 = 2 |
| Determine the hybridization of the central atom in NH3. | Nitrogen has four sigma bonds, so it undergoes sp3 hybridization. |
| Calculate the formal charge on the oxygen atom in H2O. | Formal charge = valence electrons – lone pair electrons – 1/2(bonding electrons) = 6 – 4 – 1/2(4) = 0 |
FAQs about Chemical Bonding
Q. What is a chemical bond?
Ans: A chemical bond is the pressure that holds atoms collectively in a compound, as a consequence of the attraction between charged particles (electrons and protons).
Q. What are the sorts of chemical bonds?
Ans: The predominant styles of chemical bonds are ionic bonds, covalent bonds, and metal bonds.
Q. What is an ionic bond?
Ans: An ionic bond is fashioned while electrons are transferred from one atom to another, leading to the formation of positively and negatively charged ions that appeal to every other.
Q. What is a covalent bond?
Ans: A covalent bond is fashioned when atoms share one or extra pairs of electrons to achieve balance.
Q. What are polar and nonpolar covalent bonds?
Ans: A polar covalent bond happens when electrons are shared unequally between atoms, leading to a dipole moment. A nonpolar covalent bond includes identical sharing of electrons.
