intro
Question 1:
Which sign is invariably associated with the first Electron affinity?
Topic: Electron Affinity in Atomic Physics
Correct Answer: B) Negative
- Electron affinity outlines the energy alteration when an electron is associated with a neutral atom, leading to the formation of a negative ion.
- This process is deemed exothermic, releasing energy and thus being assigned a negative sign.
- Consequently, the correct response to the question is B, "Negative".
Question 2:
How else can Bond energy be described?
Topic: Bond Energy in Chemical Bonding
Correct Answer: D) All of these
- Bond energy is the energy required to dismantle bonds in a mole of a substance.
- Each of the given terms signifies the same concept and hence, all are valid synonyms for bond energy.
- As a result, the correct answer is D, "All of these".
Question 3:
What type of bond is formed by the sideways approach of p-orbitals?
Topic: Bond Types in Chemical Bonding
Correct Answer: B) Pi (π) bond
- A Pi (π) bond is formed when there is a lateral overlap of p-orbitals.
- This type of bond is distinct from other types of bond and characterizes certain compounds and reactions.
- Therefore, the correct answer is B, "Pi (π) bond".
Question 4:
What is the measure of the degree of polarity?
Topic: Polarity in Chemical Bonding
Correct Answer: D) Dipole moment
- The measure of the degree of polarity is the dipole moment.
- The dipole moment increases with the difference in electronegativity and the distance between the charge separations.
- Thus, the correct answer is D, "Dipole moment".
Question 5:
What type of hybridization does water undergo?
Topic: Hybridization in Chemical Bonding
Correct Answer: A) sp³
- Hybridization is a model used to explain molecular geometry and atomic bonding properties.
- Water (H2O) has four pairs of electrons around the oxygen atom. These consist of two lone pairs and two pairs which are shared with the hydrogens in chemical bonds – hence hybridization is sp³.
- Therefore, the correct answer is A, "sp³".
Question 6:
What is the bond angle in SO4-2?
Topic: Molecular Geometry in Chemical Bonding
Correct Answer: C) 109.5°
- The bond angle of a molecule can be determined by its molecular geometry.
- SO4-2 has a tetrahedral geometry, which is characterized by bond angles of approximately 109.5°.
- Consequently, the correct answer is C, "109.5°".
Question 7:
According to the VSEPR theory, which electron pairs take up more space?
Topic: VSEPR Theory in Chemical Bonding
Correct Answer: A) Lone pair occupies more space than bond pair
- The VSEPR theory is used for predicting the shapes of individual molecules based upon their electron-pair composition.
- According to this theory, lone pairs repel other electron pairs more strongly than bonding pairs, hence, they occupy more space.
- Thus, the correct answer is A, "Lone pair occupies more space than bond pair".
Question 8:
Which is the correct order of natural gases in terms of increasing boiling point?
Topic: Molecular Weight and Boiling Point
Correct Answer: A) Methane < Ethane < Propane < Butane < Pentane
- The boiling point of a substance is directly proportional to its molecular weight.
- For hydrocarbons, as the number of carbon atoms increases, the molecular weight and the boiling point also increase.
- Therefore, the correct order in terms of increasing boiling point is Methane < Ethane < Propane < Butane < Pentane, which corresponds to option A.
Question 9:
According to the VSEPR theory, electron pairs are arranged around the central polyvalent atom to maintain what kind of distance?
Topic: Electron Arrangement in VSEPR Theory
Correct Answer: A) Maximum
- The Valence Shell Electron Pair Repulsion (VSEPR) theory describes the arrangement of electron pairs around a central atom.
- The fundamental principle of this theory is that electron pairs arrange themselves to minimize repulsion, which effectively maximizes the distance between them.
- Thus, the correct answer is A, "Maximum".
Question 10:
What is the bond order for an N2 molecule?
Topic: Bond Order in Molecular Bonding
Correct Answer: C) 3
- Bond order refers to the number of chemical bonds between a pair of atoms.
- In an N2 molecule, there are three bonds between the two nitrogen atoms, hence a bond order of 3.
- Therefore, the correct answer is C, "3".
Question 11:
What is the dipole moment for molecules with a linear structure?
Topic: Dipole Moment in Linear Molecules
Correct Answer: D) Zero
- A dipole moment refers to the measure of the polarity of a system of electric charges.
- For a molecule to have a dipole moment, there must be a net imbalance of charge.
- In a perfectly linear molecule, the dipoles are equal and opposite, thus cancelling each other out.
- Hence, the correct answer is D, "Zero".
Question 12:
Which of the following statements is true regarding bond energy?
Topic: Bond Energies in Chemical Bonding
Correct Answer: A) Double bond energies are higher than single bond energies
- Bond energy is the average amount of energy required to break one mole of a bond in a substance.
- Double bonds are stronger and require more energy to break as compared to single bonds.
- Thus, the correct answer is A, "Double bond energies are higher than single bond energies".
Question 13:
What type of hybridization is exhibited by ammonia (NH3)?
Topic: Hybridization in Ammonia
Correct Answer: C) sp³
- Hybridization refers to the combination of atomic orbitals to form new hybrid orbitals.
- In ammonia (NH3), nitrogen atom undergoes sp³ hybridization.
- Therefore, the correct answer is C, "sp³".
Question 14:
What is the standard unit for measuring electronegativity?
Topic: Unit of Electronegativity
Correct Answer: D) No unit
- Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.
- This tendency is expressed numerically on a scale, devoid of any specific units.
- Therefore, the correct answer is D, "No unit".
Question 15:
Which geometric shape best describes BeCl2?
Topic: Geometry of BeCl2
Correct Answer: A) Linear
- According to VSEPR theory, electron pairs arrange themselves to minimize repulsion, determining the shape of the molecule.
- In BeCl2, the two electron pairs are arranged at an angle of 180 degrees to achieve the maximum distance apart, resulting in a linear geometry.
- Hence, the correct answer is A, "Linear".
Question 16:
Which group of elements has a complete outermost shell in their atomic form?
Topic: Electron Configuration of Noble Gases
Correct Answer: A) Noble gases
- Noble gases are known for their stable electron configurations.
- They have complete outermost shells, with eight electrons (except Helium, which has two).
- Therefore, the correct answer is A, "Noble gases".
Question 17:
Where is the electron density maximum in a type of bond that involves the line joining the two nuclei?
Topic: Electron Density in Sigma Bond
Correct Answer: A) Sigma (σ) bond
- Electron density refers to the probability of an electron being present in a particular region around the nucleus.
- In a sigma bond, the electron density is maximum around the line joining the two nuclei due to the head-on approach in bond formation.
- As a result, the answer is A, "Sigma (σ) bond".
Question 18:
What bond type results from the overlap of two partially filled atomic orbitals in a way that maximizes the probability of finding the electron around the joining line of the two nuclei?
Topic: Formation of Sigma Bond
Correct Answer: D) Sigma Bond
- Sigma bonds are a type of covalent bond formed by the head-on overlapping of atomic orbitals.
- This head-on overlapping allows the electron to be most likely found around the joining line of the two nuclei.
- Therefore, the answer is D, "Sigma Bond".
Question 19:
Ionization energy corresponds to what kind of stability measure of an isolated atom?
Topic: Ionization Energy and Atomic Stability
Correct Answer: B) Qualitative
- Ionization energy is the energy required to remove an electron from an atom in its gaseous state.
- It serves as a qualitative measure of the stability of an isolated atom - the higher the ionization energy, the more stable the atom.
- Hence, the correct answer is B, "Qualitative".
Question 20:
Which chemical bond boasts the highest bond energy?
Topic: Bond Energy in Chemical Bonds
Correct Answer: C) C ≡ O
- In chemistry, bond energy refers to the amount of energy required to break a bond between two atoms.
- Among single, double, and triple bonds, the latter, like C ≡ O, contain the highest amount of bond energy because of the multiple bonds in place.
- Thus, the correct choice is C, "C ≡ O".
Question 21:
What kind of nature do elements possessing moderate ionization energy values generally exhibit?
Topic: Ionization Energy and Element Nature
Correct Answer: C) Metalloids
- Ionization energy is a significant factor in determining the nature of elements – metals, non-metals, or metalloids.
- Metals have lower ionization energies making their outer electrons easily removable, while non-metals possess high ionization energies with tightly bound outer electrons.
- Elements with moderate ionization energies, therefore, tend to be metalloids.
Question 22:
How does the s-character influence the bond length?
Topic: Role of S-character in Bond Length
Correct Answer: B) Increased s-character leads to shorter bond length
- The s-character refers to the participation of the s orbital in bonding.
- Electrons in s orbitals are typically closer to the nucleus and more tightly bound than those in p orbitals.
- Consequently, a greater s-character implies a shorter bond length.
- Therefore, the correct answer is B, "Increased s-character leads to shorter bond length".
Question 23:
Which among the below options participates in determining the geometry of molecules according to the VSEPR theory?
Topic: Determinants of Molecular Geometry in VSEPR Theory
Correct Answer: C) Both Lone and Bond pairs
- The Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules based on the number of electron pairs surrounding their central atoms.
- Both bond pairs (pairs of electrons forming a bond) and lone pairs (pairs of electrons not involved in bonding) play significant roles in determining the molecular geometry according to the VSEPR theory.
- Consequently, the right answer is C, "Both Lone and Bond pairs".
Question 24:
What term is used to describe the screening effect observed between shells due to intervening electrons?
Topic: Intervening Electron Effects on Shells
Correct Answer: C) Shielding effect
- In atomic structure, there is a phenomenon where the outer shell electrons are shielded from the positive influence of the nucleus by the intervening electrons.
- This effect is known as the shielding effect.
- Hence, C, "Shielding effect", is the correct choice.
Question 25:
Ionization energy serves as a measure of which characteristic?
Topic: Ionization Energy and Elemental Character
Correct Answer: A) Metallic character
- Ionization energy, the energy required to remove an electron from an atom, can reflect the character of an element.
- Elements with high ionization energies typically have non-metallic characters as their outer electrons are tightly bound. Contrarily, elements with lower ionization energies are often metals, as their outer electrons can be easily removed.
- Therefore, choice A, "Metallic character", is the correct answer.
Question 26:
Who developed the VSEPR theory that elucidates the shapes of molecules for non-transition elements?
Topic: Founders of VSEPR Theory
Correct Answer: B) Nylholm and Gillespie
- The VSEPR theory, which stands for Valence Shell Electron Pair Repulsion theory, provides an explanation for the shapes of molecules, especially those of non-transition elements.
- This significant theory was developed by two chemists, Nylholm and Gillespie.
- Thus, the correct answer is B, "Nylholm and Gillespie".
Question 27:
Which of the following is not an absolute term of the element?
Topic: Absolute Terms of an Element
Correct Answer: C) Electronegativity
- In chemistry, certain properties of elements are considered "absolute terms". These are properties that can be precisely measured.
- However, electronegativity, which refers to an atom's ability to attract shared electrons, is not considered an absolute term as it cannot be directly measured and must be calculated based on other atomic or molecular properties.
- Hence, the correct answer is C, "Electronegativity".
Question 28:
What describes the molecular structure of an SO3 molecule?
Topic: Molecular Structure of SO3
Correct Answer: D) Perfectly triangular
- The shape of a molecule is determined by its molecular structure, which is defined by the arrangement of atoms in the molecule.
- The SO3 molecule, composed of one sulfur atom and three oxygen atoms, exhibits a perfectly triangular molecular structure.
- Therefore, the correct answer is D, "Perfectly triangular".
Question 29:
How many vertices are present in a tetrahedral structure?
Topic: Tetrahedral Geometry
Correct Answer: B) 4
- A shape's geometry can be determined by observing its key attributes, such as vertices or corners.
- In the case of a tetrahedral structure, it is characterized by having four vertices.
- Therefore, the appropriate answer is B, "4".
Question 30:
Given that the second ionization energy of an element is 1200 and the third ionization energy is 5000, what is the valency of this element?
Topic: Determining Valency from Ionization Energy
Correct Answer: B) 2
- The valency of an element can be deduced from the ionization energy values.
- Ionization energy is the energy needed to remove an electron from an atom.
- Notably, a substantial difference between consecutive ionization energies can indicate the valency.
- If there's a large gap between the second and third ionization energies, the valency is likely two.