Atoms, Molecules and Stoichiometry: Interactive Learning Quizzes

Question 1

Identify the correct electronic configuration of a nitrogen atom in its ground state:

Accepted Answer

1s²2s²2p³

Answer

1s²2s³2p²

Answer

1s²2s⁴2p¹

Answer

1s22s5

Question 2

Which carbon isotope contains eight neutrons?

Accepted Answer

13C

Answer

12C

Answer

14C

Answer

15C

Question 3

Determine the empirical formula of a compound with 40% carbon and 60% oxygen by mass:

Accepted Answer

CO

Answer

CO2

Answer

C2O

Answer

C2O2

Question 4

Which of the following is NOT a fundamental subatomic particle?

Accepted Answer

Meson

Answer

Proton

Answer

Electron

Answer

Neutron

Question 5

What is the empirical formula of a compound containing 40% carbon and 60% oxygen by weight?

Accepted Answer

CO2

Answer

CO

Answer

C2O

Answer

C3O2

Question 6

What is the balanced chemical equation for the reaction between magnesium and hydrochloric acid?

Accepted Answer

Mg + 2HCl → MgCl2 + H2

Answer

Mg + HCl → MgCl + H

Answer

2Mg + HCl → 2MgCl + H

Answer

Mg + HCl → MgCl2 + 2H

Question 7

Which of the following is a strong acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Phosphoric acid

Answer

Carbonic acid

Question 8

Which of the following represents the correct electronic configuration for oxygen?

Accepted Answer

[He] 2s² 2p⁴

Answer

[He] 2s² 2p²

Answer

[He] 2s¹ 2p³

Answer

[He] 1s² 2s² 2p⁴

Question 9

Which compound among the following options is classified as an ionic compound?

Accepted Answer

Sodium chloride

Answer

Hydrogen chloride

Answer

Water

Answer

Carbon dioxide

Question 10

Identify the most electronegative element among the following choices.

Accepted Answer

Fluorine

Answer

Chlorine

Answer

Bromine

Answer

Iodine

Question 11

Which type of bond is generally considered the strongest?

Accepted Answer

Ionic bond

Answer

Covalent bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 12

Identify the polar molecule among the following options.

Accepted Answer

Water

Answer

Nitrogen

Answer

Carbon dioxide

Answer

Methane

Question 13

Which of the following intermolecular forces is considered to be the weakest?

Accepted Answer

London dispersion forces

Answer

Hydrogen bonding

Answer

Dipole-dipole forces

Answer

Ion-dipole forces

Question 14

Determine the correct electron configuration for chlorine.

Accepted Answer

1s² 2s² 2p⁶ 3s² 3p⁵

Answer

1s² 2s² 2p⁶ 3s² 3p⁶

Answer

1s² 2s² 2p⁶ 3s² 3p⁴

Answer

1s² 2s² 2p⁶ 3s¹ 3p⁵

Question 15

Calculate the molar mass of sodium chloride (NaCl).

Accepted Answer

58.44 g/mol

Answer

22.99 g/mol

Answer

35.45 g/mol

Answer

70.90 g/mol

Question 16

Identify the bond type formed by sharing electrons between atoms.

Accepted Answer

Covalent bond

Answer

Ionic bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 17

Identify the substance that speeds up a chemical reaction without being consumed.

Accepted Answer

Enzyme

Answer

Reactant

Answer

Product

Answer

Inert substance

Question 18

Determine the equilibrium constant for a reaction that shows no net change.

Accepted Answer

1

Answer

0

Answer

K > 1

Answer

K < 1

Question 19

Which of the following elements is NOT a noble gas?

Accepted Answer

Chlorine

Answer

Helium

Answer

Neon

Answer

Argon

Question 20

A covalent bond is formed when:

Accepted Answer

Electrons are shared between atoms

Answer

Electrons are transferred from one atom to another

Answer

Ions are attracted to each other

Answer

Atoms are held together by metallic bonds

Question 21

The empirical formula of a compound represents:

Accepted Answer

The simplest whole number ratio of atoms of each element in a molecule

Answer

The exact number of atoms of each element in a molecule

Answer

The molecular weight of the compound

Answer

The structural formula of the compound

Question 22

Which of the following is identified as the limiting reactant?

Accepted Answer

The reactant that is present in the smallest amount relative to its stoichiometric ratio

Answer

The reactant that is completely consumed in a reaction

Answer

The reactant that is present in excess

Answer

The reactant that reacts most quickly

Question 23

The molar mass of a substance is defined as:

Accepted Answer

The mass of one mole of the substance

Answer

The mass of one atom or molecule of the substance

Answer

The ratio of the mass to the volume of the substance

Answer

The density of the substance

Question 24

The pH of a solution can be accurately measured using:

Accepted Answer

A pH meter

Answer

A litmus paper

Answer

A burette

Answer

A calorimeter

Question 25

Identify the metalloid in the following list:

Accepted Answer

Silicon

Answer

Oxygen

Answer

Sodium

Answer

Chlorine

Question 26

Calculate the molar mass of carbon dioxide (CO2):

Accepted Answer

44 g/mol

Answer

28 g/mol

Answer

60 g/mol

Answer

32 g/mol

Question 27

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

Accepted Answer

sp3

Answer

sp

Answer

sp2

Answer

sp3d

Question 28

Identify the type of bond formed between two non-metal atoms:

Accepted Answer

Covalent bond

Answer

Ionic bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 29

Which topic is not covered in the unit '1.2 Atoms, Molecules and Stoichiometry'?

Accepted Answer

Thermodynamics

Answer

Atomic structure

Answer

Chemical bonding

Answer

Stoichiometry

Question 30

Which of the following elements is a noble gas?

Accepted Answer

Argon

Answer

Sodium

Answer

Chlorine

Answer

Calcium

Question 31

A covalent bond is formed when atoms:

Accepted Answer

Share electrons

Answer

Transfer electrons to each other

Answer

Attract each other through electrostatic forces

Answer

Repel each other due to like charges

Question 32

Which of the following compounds is an acid?

Accepted Answer

HCl

Answer

NaOH

Answer

NaCl

Answer

NH₃

Question 33

A reducing agent:

Accepted Answer

Loses electrons and is reduced

Answer

Gains electrons and is oxidized

Answer

Accepts protons and is oxidized

Answer

Donates protons and is reduced

Question 34

A Lewis acid is a substance that:

Accepted Answer

Accepts an electron pair

Answer

Donates an electron pair

Answer

Forms a covalent bond with a metal

Answer

Forms an ionic bond with a non-metal

Question 35

Which element is NOT a noble gas?

Accepted Answer

Oxygen

Answer

Helium

Answer

Neon

Answer

Argon

Question 36

Identify the element that is NOT a noble gas:

Accepted Answer

Oxygen

Answer

Helium

Answer

Argon

Answer

Xenon

Question 37

The atomic number of an atom represents the number of:

Accepted Answer

Protons

Answer

Electrons

Answer

Neutrons

Answer

Quarks

Question 38

Which of the following bonds is a covalent bond?

Accepted Answer

Hydrogen molecule (H-H)

Answer

Sodium chloride (Na-Cl)

Answer

Magnesium oxide (Mg-O)

Answer

Potassium fluoride (K-F)

Question 39

A balanced chemical equation primarily shows:

Accepted Answer

The equal number of atoms of each element on both sides

Answer

The type of reaction occurring

Answer

The heat change associated with the reaction

Answer

The reaction rate

Question 40

Identify the strong electrolyte among the following compounds:

Accepted Answer

Hydrochloric acid (HCl)

Answer

Methanol (CH₃OH)

Answer

Glucose (C₆H₁₂O₆)

Answer

Ammonia (NH₃)

Question 41

The molar mass of a compound is defined as:

Accepted Answer

The mass of one mole of the compound

Answer

The sum of the atomic masses of its constituent elements

Answer

The density of the compound

Answer

The volume of one mole of the compound

Question 42

The half-life of a radioactive isotope signifies:

Accepted Answer

The time taken for half of the radioactive atoms to decay

Answer

The time taken for all radioactive atoms to decay

Answer

The time taken for the activity of the isotope to reduce by half

Answer

The time taken for the mass of the isotope to reduce by half

Question 43

Which of the following statements about the periodic table is **incorrect**?

Accepted Answer

The periodic table is a dynamic tool that is subject to frequent updates.

Answer

Elements are arranged in order of increasing atomic number.

Answer

Elements in the same group have similar chemical properties.

Answer

Metals are generally located on the left-hand side of the periodic table.

Question 44

Which of the following molecules is non-polar?

Accepted Answer

CH4

Answer

H2O

Answer

NH3

Answer

HCl

Question 45

What is the molar mass of sodium chloride (NaCl)?

Accepted Answer

58.44 g/mol

Answer

70.90 g/mol

Answer

44.01 g/mol

Answer

64.06 g/mol

Question 46

What is the balanced chemical equation for the reaction between sodium and water?

Accepted Answer

2Na + 2H₂O → 2NaOH + H₂

Answer

Na + 2H₂O → 2NaOH + H₂

Answer

Na + H₂O → NaOH + H₂

Answer

2Na + H₂O → NaOH + H₂

Question 47

Which of the following is a strong acid?

Accepted Answer

HCl

Answer

H2SO3

Answer

NH4OH

Answer

CH3COOH