The nucleus of an atom contains:
a) Electrons
b) Protons and Neutrons
c) Electrons and Protons
d) Neutrons only
The atomic number of an element is equal to the number of:
a) Protons in the nucleus
b) Neutrons in the nucleus
c) Electrons in the nucleus
d) Neutrons and protons combined
Which of the following particles has a negative charge?
a) Proton
b) Neutron
c) Electron
d) Positron
What is the charge of a neutron?
a) Positive
b) Negative
c) Neutral
d) Double positive
The number of neutrons in an atom can be determined by:
a) Atomic number – Mass number
b) Mass number – Atomic number
c) Atomic number + Mass number
d) Number of electrons – Number of protons
Isotopes of an element have the same number of:
a) Protons and neutrons
b) Neutrons and electrons
c) Protons
d) Electrons
The emission of an alpha particle results in:
a) Decrease in atomic number by 2 and mass number by 4
b) Increase in atomic number by 2 and mass number by 4
c) No change in atomic number but decrease in mass number by 4
d) Decrease in atomic number by 4 and mass number by 2
In a beta decay, a neutron is converted into:
a) Proton and electron
b) Proton and positron
c) Electron and neutrino
d) Neutron and positron
The primary force holding the nucleus together is:
a) Gravitational force
b) Electromagnetic force
c) Strong nuclear force
d) Weak nuclear force
What is the energy released during nuclear reactions primarily due to?
a) Conversion of mass into energy
b) Breaking of atomic bonds
c) Formation of new chemical compounds
d) Excitation of electrons
The mass number of an atom is the sum of:
a) Protons and neutrons
b) Protons and electrons
c) Neutrons and electrons
d) Protons, neutrons, and electrons
What does the term “isobar” refer to?
a) Atoms with the same atomic number but different mass numbers
b) Atoms with the same mass number but different atomic numbers
c) Atoms with the same number of neutrons
d) Atoms with different numbers of protons and neutrons
In a nuclear reaction, the conservation of which quantity is crucial?
a) Mass only
b) Energy only
c) Mass and energy
d) Charge only
The concept of “half-life” refers to:
a) The time taken for half of the atoms in a sample to decay
b) The time required for a radioactive atom to lose half its mass
c) The time taken for half of the electrons to be emitted
d) The time required for half of the sample to become stable
Which of the following is not a type of radioactive decay?
a) Alpha decay
b) Beta decay
c) Gamma decay
d) Delta decay
Gamma radiation is characterized by:
a) High mass and high charge
b) No mass and no charge
c) Moderate mass and positive charge
d) High mass and no charge
The Rutherford gold foil experiment demonstrated that:
a) Atoms are mostly empty space
b) Electrons are embedded in a positive sphere
c) Electrons orbit the nucleus in fixed paths
d) Neutrons are located in the nucleus
In the Bohr model of the atom, electrons:
a) Move in elliptical orbits around the nucleus
b) Move in fixed orbits around the nucleus
c) Are located randomly in a cloud around the nucleus
d) Are stationary in fixed positions
The uncertainty principle, formulated by Heisenberg, states that:
a) The exact position and momentum of an electron cannot be known simultaneously
b) Electrons have fixed orbits around the nucleus
c) Electrons can be predicted with certainty using classical mechanics
d) Atomic nuclei are stable unless acted upon by external forces
Which particle is often involved in nuclear reactions but has no charge?
a) Proton
b) Neutron
c) Electron
d) Positron
What is the primary difference between isotopes of the same element?
a) Number of protons
b) Number of electrons
c) Number of neutrons
d) Number of energy levels
The principle of conservation of charge implies that:
a) The total charge before and after a nuclear reaction remains the same
b) The mass of an atom is conserved in a nuclear reaction
c) Energy is neither created nor destroyed
d) The number of protons remains unchanged in a chemical reaction
Which force is responsible for the repulsion between protons in the nucleus?
a) Strong nuclear force
b) Electromagnetic force
c) Gravitational force
d) Weak nuclear force
The neutron was discovered by:
a) Ernest Rutherford
b) Niels Bohr
c) James Chadwick
d) J.J. Thomson
An atom with an equal number of protons and electrons is:
a) Electrically neutral
b) Positively charged
c) Negatively charged
d) An isotope
Which of the following has the highest penetrating power?
a) Alpha particles
b) Beta particles
c) Gamma rays
d) Neutrons
In a chemical reaction, which of the following quantities remains unchanged?
a) Atomic number
b) Mass number
c) Nuclear binding energy
d) Number of neutrons
The term “binding energy” refers to:
a) The energy required to remove an electron from an atom
b) The energy required to break up a nucleus into its constituent protons and neutrons
c) The energy required to form a covalent bond
d) The energy released during a chemical reaction
The concept of “quantum” refers to:
a) A continuous range of energy levels
b) The smallest discrete amount of energy
c) The total energy of an atom
d) The random motion of particles
Which model of the atom introduced the concept of quantized energy levels?
a) Rutherford model
b) Bohr model
c) Thomson model
d) Quantum mechanical model
The energy required to remove an electron from an atom in its gaseous state is called:
a) Electronegativity
b) Ionization energy
c) Electron affinity
d) Atomic radius
In the quantum mechanical model, electrons are described by:
a) Fixed orbits
b) Probabilistic orbitals
c) Classical paths
d) Circular orbits
The emission of gamma rays from a nucleus is typically associated with:
a) A change in the atomic number
b) A change in the mass number
c) A change in the energy state of the nucleus
d) The emission of an alpha particle
The process by which an unstable nucleus releases energy by emitting radiation is known as:
a) Nuclear fusion
b) Nuclear fission
c) Radioactive decay
d) Chemical reaction
The charge of a proton is:
a) +1
b) -1
c) 0
d) +2
The mass of an electron is approximately:
a) Equal to the mass of a proton
b) Equal to the mass of a neutron
c) Much smaller than the mass of a proton or neutron
d) Larger than the mass of a proton
The concept of quantization of energy levels was introduced by:
a) Niels Bohr
b) Albert Einstein
c) Werner Heisenberg
d) Erwin Schrödinger
Which particle is considered the “heavy” particle in the nucleus?
a) Electron
b) Proton
c) Neutron
d) Photon
Which type of radioactive decay increases the atomic number of the element by one?
a) Alpha decay
b) Beta decay
c) Gamma decay
d) Positron emission
The nucleus of an atom is held together by:
a) Electromagnetic force
b) Gravitational force
c) Strong nuclear force
d) Weak nuclear force
