#1
Who proposed the atomic theory that states that atoms are indivisible and indestructible?
John Dalton
Ernest Rutherford
Niels Bohr
Democritus
#2
What fundamental law states that mass cannot be created or destroyed in a chemical reaction?
Law of Multiple Proportions
Law of Definite Proportions
Law of Conservation of Mass
Law of Combining Volumes
#3
What does the Law of Definite Proportions state?
Atoms of different elements combine in whole-number ratios to form compounds.
The mass of reactants equals the mass of products in a chemical reaction.
All matter is composed of tiny, indivisible particles called atoms.
A compound always contains the same elements in the same proportion by mass.
#4
What is the significance of the Law of Conservation of Mass in chemistry?
It explains the behavior of gases at different temperatures and pressures.
It describes the relationship between the energy and temperature of a system.
It states that matter cannot be created or destroyed in a chemical reaction.
It explains the behavior of elements in the periodic table.
#5
Which of the following statements best describes Rutherford's gold foil experiment?
It showed that atoms are mostly empty space with a small, dense nucleus.
It discovered the electron's charge-to-mass ratio.
It demonstrated that electrons orbit the nucleus in fixed paths.
It proved the existence of isotopes.
#6
Who proposed the modern atomic theory that states atoms of an element are identical in size, mass, and chemical properties?
John Dalton
JJ Thomson
Ernest Rutherford
Niels Bohr
#7
Who proposed the plum pudding model of the atom?
Ernest Rutherford
JJ Thomson
Niels Bohr
Democritus
#8
Who proposed the planetary model of the atom?
Ernest Rutherford
JJ Thomson
Niels Bohr
Democritus
#9
Who proposed the Law of Multiple Proportions?
John Dalton
JJ Thomson
Dmitri Mendeleev
Joseph Proust
#10
What is the key idea behind Avogadro's Law?
Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
The total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases.
The rate of a chemical reaction is directly proportional to the concentrations of the reacting substances.
The energy of a system remains constant if no energy is added or removed.
#11
Which subatomic particle was discovered first?
Proton
Electron
Neutron
Nucleus
#12
What was the conclusion drawn from the Millikan oil drop experiment?
The existence of the neutron.
The charge of the electron.
The mass of the electron.
The atomic number of an element.
#13
Who discovered the neutron?
Ernest Rutherford
James Chadwick
Niels Bohr
JJ Thomson
#14
What discovery led to the abandonment of the plum pudding model of the atom?
Discovery of the electron
Discovery of the neutron
Discovery of the nucleus
Discovery of isotopes
#15
What concept did Niels Bohr introduce to explain the stability of electrons in specific orbits?
Quantum mechanics
Wave-particle duality
Energy levels
Electron cloud
#16
Who proposed the concept of atomic number?
John Dalton
JJ Thomson
Dmitri Mendeleev
Henry Moseley