Chemical Foundations: Master the Basics of Chemistry for Mechanical Engineers

Question 1

How does the ionization energy of an atom change as you move from left to right across a period and from top to bottom down a group in the periodic table?

Accepted Answer

Ionization energy generally increases across a period and decreases down a group.

Answer

Ionization energy generally decreases across a period and increases down a group.

Answer

Ionization energy remains relatively constant across a period and down a group.

Answer

Ionization energy increases across a period and remains relatively constant down a group.

Question 2

Which of the following is NOT one of the four primary quantum numbers used to describe electrons in an atom?

Accepted Answer

j

Answer

n

Answer

l

Answer

m

Question 3

Within a period of the periodic table, how does the atomic radius change as you move from left to right?

Accepted Answer

Decreases

Answer

Increases

Answer

Stays the same

Answer

Fluctuates

Question 4

Which fundamental principle underpins Quantum Theory?

Accepted Answer

Electron energy levels are distinct and quantized.

Answer

Electrons continuously orbit the nucleus in fixed, circular paths.

Answer

Atomic nuclei consist only of protons and neutrons, not electrons.

Answer

Chemical reactions occur when atoms exchange, gain, or lose electrons.

Question 5

In the periodic table, how does an element's atomic number generally influence its electronegativity?

Accepted Answer

Electronegativity increases with increasing atomic number.

Answer

Electronegativity decreases with increasing atomic number.

Answer

Electronegativity stays the same regardless of atomic number.

Question 6

Which atomic property is NOT directly influenced by the electron arrangement of the atom?

Accepted Answer

Magnetic susceptibility

Answer

Atomic radius

Answer

Ionization energy

Answer

Electronegativity

Question 7

How does an element's electronic configuration relate to its position on the periodic table?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Accepted Answer

The electronic configuration of an element determines its chemical properties.

Answer

The number of electrons in an element's outermost energy level is equal to its atomic number.

Answer

The periodic table is organized solely by increasing atomic mass.

Question 8

Which factor governs the sequence in which electrons occupy atomic orbitals, as per the Aufbau principle?

Accepted Answer

Ascending energy levels

Answer

Descending energy levels

Answer

Ascending atomic number

Answer

Descending atomic number

Question 9

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number (l)

Answer

Principal quantum number (n)

Answer

Magnetic quantum number (ml)

Answer

Spin quantum number (ms)

Question 10

How does the difference in electronegativity between two atoms affect the polarity of the bond they form?

Accepted Answer

The greater the difference, the more polar the bond.

Answer

The smaller the difference, the more polar the bond.

Answer

Electronegativity has no effect on bond polarity.

Answer

Bond polarity is independent of electronegativity.

Question 11

How do quantum numbers contribute to our understanding of atomic structure and electron configurations?

Accepted Answer

They define the energy, shape, and orientation of atomic orbitals.

Answer

They apply only to specific elements.

Answer

They predict chemical reactivity and bonding behavior.

Answer

They are unrelated to electron arrangement.

Question 12

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number (l)

Answer

Principal quantum number (n)

Answer

Magnetic quantum number (ml)

Answer

Spin quantum number (ms)

Question 13

Which of the following is NOT a subatomic particle found within an atom?

Accepted Answer

Photon

Answer

Proton

Answer

Electron

Answer

Neutron

Question 14

Which of the following properties is characteristic of ionic bonds?

Accepted Answer

Electrical conductivity in the molten state and aqueous solutions

Answer

Low melting and boiling points

Answer

Solubility in nonpolar solvents

Answer

Formation of amorphous solids with irregular structures

Question 15

Which of the following is NOT a quantum number used to describe an electron in an atom?

Accepted Answer

Atomic weight

Answer

Principal quantum number (n)

Answer

Angular momentum quantum number (l)

Answer

Magnetic quantum number (ml)

Question 16

Which particle is NOT found within an atom?

Accepted Answer

Quark

Answer

Proton

Answer

Neutron

Answer

Electron

Question 17

Which subatomic particle is NOT located within the nucleus of an atom?

Accepted Answer

Valence electron

Answer

Proton

Answer

Neutron

Question 18

In a chemical reaction at equilibrium, what happens to the equilibrium position if the concentrations of the reactants are increased while the temperature remains constant?

Accepted Answer

The equilibrium shifts to the product side.

Answer

The equilibrium shifts to the reactant side.

Answer

The equilibrium constant increases.

Answer

No change occurs to the equilibrium position.

Question 19

Which property is NOT a characteristic of acids?

Accepted Answer

Have a pH value greater than 7

Answer

Release hydrogen ions (H+) in water

Answer

Turn litmus paper red

Answer

React with bases to form salts and water

Question 20

In a neutral atom, what is the relationship between the number of protons and electrons?

Accepted Answer

Equal

Answer

Protons greater than electrons

Answer

Protons less than electrons

Question 21

Which quantum number primarily governs the size and energy level of an atomic orbital?

Accepted Answer

Principal Quantum Number (n)

Answer

Azimuthal Quantum Number (l)

Answer

Magnetic Quantum Number (ml)

Answer

Spin Quantum Number (ms)

Question 22

In an exothermic reaction at constant pressure, if the temperature decreases, what is the sign of the enthalpy change?

Accepted Answer

Negative

Answer

Positive

Answer

Zero

Question 23

Predict the type of chemical bond formed between calcium (Ca) and oxygen (O) in calcium oxide (CaO) based on their positions in the periodic table. Explain your reasoning.

Accepted Answer

Ionic

Answer

Covalent

Answer

Hydrogen

Answer

Metallic

Question 24

In a chemical system at equilibrium, how does increasing the concentration of a reactant affect the equilibrium position?

Accepted Answer

The equilibrium position shifts towards the products.

Answer

The equilibrium position shifts towards the reactants.

Answer

The equilibrium position remains unchanged.

Question 25

Which of the following accurately describes valence electrons?

Accepted Answer

Electrons in the outermost energy level that influence an atom's chemical behavior

Answer

Electrons in the innermost energy level, tightly bound to the nucleus

Answer

Electrons in the middle energy levels, with limited impact on chemical properties

Answer

Electrons gained or lost in chemical reactions, not confined to the outermost energy level

Question 26

In the quantum mechanical model of atomic structure, electrons are arranged in:

Accepted Answer

Discrete energy levels with sublevels containing a specific number of electrons

Answer

Fixed circular orbits with specific radii

Answer

Randomly distributed throughout the atom, forming a continuous energy spectrum

Answer

Localized within the nucleus, forming a dense central core

Question 27

According to quantum theory, how does the wave-particle duality of electrons influence our understanding of atomic structure?

Accepted Answer

The wave-like nature of electrons introduces the concept of electron orbitals, which represent the probable locations of electrons.

Answer

Electrons behave exclusively as particles within an atom, with their wave-like properties being insignificant.

Answer

The wave-particle duality of electrons has no impact on the arrangement and behavior of electrons in an atom.

Question 28

Which of the following is not a quantum number used to describe an electron?

Accepted Answer

Parity

Answer

Principal quantum number (n)

Answer

Azimuthal quantum number (l)

Answer

Magnetic quantum number (ml)

Question 29

In an electrochemical cell, the electric current is generated by the movement of electrons. Which of the following factors does NOT affect the magnitude of this current?

Accepted Answer

Identity of the salt bridge

Answer

Concentration of the reactants

Answer

Surface area of the electrodes

Answer

Temperature

Question 30

In electrochemistry, which factor determines the magnitude of the potential difference (∆E) of an electrochemical cell?

Accepted Answer

Standard reduction potentials of half-reactions

Answer

Concentrations of reactants and products

Answer

Temperature of the cell

Answer

Surface area of electrodes

Question 31

How does the number of neutrons in an element compare to its atomic number?

Accepted Answer

Can be equal to, greater than, or less than

Answer

Always greater

Answer

Always less

Answer

Always equal

Question 32

Which property is characteristic of solids?

Accepted Answer

Fixed intermolecular distances

Answer

Indefinite shape and volume

Answer

High fluidity

Answer

Low density

Question 33

Which element has the greatest ability to attract electrons?

Accepted Answer

Fluorine

Answer

Sodium

Answer

Carbon

Question 34

In the redox reaction below, identify the oxidizing and reducing agents. Provide justifications for your answers:

$$2Fe^{3+}(aq) + 2I^-(aq) → 2Fe^{2+}(aq) + I_2(s)$$

Accepted Answer

Oxidizing agent: $Fe^{3+}$, Reducing agent: $I^-$

Answer

Oxidizing agent: $I^-$, Reducing agent: $Fe^{3+}$

Answer

Oxidizing agent: $I_2$, Reducing agent: $Fe^{2+}$

Answer

Oxidizing agent: $Fe^{2+}$, Reducing agent: $I_2$

Question 35

Determine the molecular geometry of a compound with a central atom exhibiting **sp³ hybridization**.

Accepted Answer

Tetrahedral

Answer

Linear

Answer

Trigonal planar

Answer

T-shaped

Question 36

Describe the trends in electronegativity and atomic radius across a period of the periodic table. Explain the relationship between these trends and the chemical properties of the elements.

Accepted Answer

Electronegativity increases, while atomic radius decreases.

Answer

Electronegativity increases, while atomic radius increases.

Answer

Electronegativity decreases, while atomic radius increases.

Answer

Electronegativity decreases, while atomic radius decreases.

Question 37

In methane, carbon undergoes sp3 hybridization. How does this hybridization affect the molecular geometry and polarity of methane?

Accepted Answer

Tetrahedral geometry and nonpolar

Answer

Linear geometry and polar

Answer

Trigonal planar geometry and nonpolar

Answer

Bent geometry and polar

Question 38

What is chemical equilibrium, and how does it relate to reversible chemical reactions?

Accepted Answer

A state where the forward and reverse reactions occur at the same rate, keeping the concentrations of reactants and products constant.

Answer

A state where the concentrations of reactants and products are equal.

Answer

A state where no further chemical change can occur.

Answer

A state where the products are completely consumed.

Question 39

How are the elements organized on the periodic table?

Accepted Answer

By increasing atomic number

Answer

By increasing atomic mass

Answer

By increasing electronegativity

Answer

By increasing ionization energy

Question 40

Identify the subatomic particle that is NOT fundamental.

Accepted Answer

Quark

Answer

Proton

Answer

Electron

Answer

Neutron

Question 41

Specify the force responsible for the attraction between protons and electrons.

Accepted Answer

Electrical force

Answer

Gravitational force

Answer

Magnetic force

Answer

Nuclear force

Question 42

Indicate the type of bond formed when electron sharing occurs between atoms.

Accepted Answer

Covalent bond

Answer

Metallic bond

Answer

Ionic bond

Answer

Hydrogen bond

Question 43

Identify the gas that is NOT a greenhouse gas.

Accepted Answer

Oxygen

Answer

Carbon dioxide

Answer

Water vapor

Answer

Methane

Question 44

Identify the exothermic reaction from the following options.

Accepted Answer

CaO(s) + H2O(l) → Ca(OH)2(s) + heat

Answer

NaCl(s) + H2O(l) → NaCl(aq) + H2O(l)

Answer

CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)

Answer

N2(g) + 3 H2(g) → 2 NH3(g)

Question 45

Specify the hybridization of the carbon atom in CH4 (methane).

Accepted Answer

sp3

Answer

sp

Answer

sp2

Answer

sp3d

Question 46

Identify the strong electrolyte from the following options.

Accepted Answer

Sodium chloride

Answer

Ethanol

Answer

Sucrose

Answer

Ammonia

Question 47

Water has a remarkably high boiling point. Which type of intermolecular force is the main reason for this?

Accepted Answer

Hydrogen bonding

Answer

Dipole-dipole forces

Answer

London dispersion forces

Answer

Ion-dipole forces

Question 48

Which of the following statements about isomers is true?

Accepted Answer

Isomers have the same molecular formula but different structural formulas.

Answer

Isomers always have the same molecular properties.

Answer

Isomerism is only found in organic compounds.

Answer

Isomers have the same structural formulas.

Question 49

How does quantum superposition affect electrons within an atom?

Accepted Answer

Electrons can occupy multiple energy levels at the same time.

Answer

Electrons always reside in the lowest available energy level.

Answer

Electrons travel in circular paths around the nucleus.

Answer

Electrons change energy levels by absorbing or releasing photons.

Question 50

Within a period of the periodic table, how does ionization energy change in relation to atomic radius?

Accepted Answer

Ionization energy increases, while atomic radius decreases.

Answer

Both ionization energy and atomic radius increase.

Answer

Both ionization energy and atomic radius decrease.

Answer

Ionization energy decreases, while atomic radius increases.

Question 51

Which of these elements is NOT a noble gas?

Accepted Answer

Oxygen

Answer

Helium

Answer

Xenon

Answer

Argon

Question 52

Which of the following is NOT a subatomic particle that makes up an atom?

Accepted Answer

Molecule

Answer

Electron

Answer

Neutron

Answer

Proton

Question 53

Which type of chemical bond is formed by the electrostatic attraction between oppositely charged ions?

Accepted Answer

Ionic bond

Answer

Covalent bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 54

Which group in the periodic table contains the element chlorine?

Accepted Answer

Group 17

Answer

Group 1

Answer

Group 16

Answer

Group 18

Question 55

Which of the following electron configurations represents a stable noble gas?

Accepted Answer

1s²2s²2p⁶

Answer

1s²2s²2p⁴

Answer

1s²2s²2p⁶3s²

Answer

1s²2s²2p⁶3s¹

Question 56

What is the hybridization of the carbon atom in methane (CH₄)?

Accepted Answer

sp³

Answer

sp

Answer

sp²

Answer

sp³d

Question 57

What is the pH of a solution with a hydrogen ion concentration of 10⁻⁷ M?

Accepted Answer

7

Answer

1

Answer

4

Answer

10

Question 58

Which of the following substances is classified as a strong electrolyte?

Accepted Answer

Sodium chloride (NaCl)

Answer

Methanol (CH₃OH)

Answer

Ammonia (NH₃)

Answer

Glucose (C₆H₁₂O₆)

Question 59

What is the rate law for a bimolecular reaction, which is second order with respect to both reactants A and B?

Accepted Answer

Rate = k[A][B]²

Answer

Rate = k[A][B]

Answer

Rate = k[A]²[B]

Answer

Rate = k[A][B]⁻¹

Question 60

Which of the following electron configurations represents a neutral nitrogen atom in its ground state?

Accepted Answer

1s²2s²2p³

Answer

1s²2s³2p²

Answer

1s²2s²3p³

Answer

1s²2s²2p⁴

Question 61

Which type of chemical bond forms when atoms share electrons?

Accepted Answer

Covalent bond

Answer

Hydrogen bond

Answer

Ionic bond

Answer

Metallic bond

Question 62

Determine the hybridization of the carbon atom in methane (CH₄).

Accepted Answer

sp3

Answer

sp2

Answer

sp

Answer

sp3d

Question 63

Which of the following compounds is a strong acid?

Accepted Answer

Hydrochloric acid (HCl)

Answer

Ammonium hydroxide (NH₄OH)

Answer

Carbonic acid (H₂CO₃)

Answer

Acetic acid (CH₃COOH)

Question 64

Determine the enthalpy change for the reaction: CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g).

Accepted Answer

-890 kJ/mol

Answer

890 kJ/mol

Answer

-222.5 kJ/mol

Answer

-445 kJ/mol