Subatomic Particles Quiz

Who is credited with discovering the electron?

• Rutherford

• Thomson

• Chadwick

• Bohr

Answer explanation

J.J. Thomson is credited with discovering the electron in 1897 through his experiments with cathode rays, demonstrating that they were composed of negatively charged particles, which he named electrons.

Which of the following particles has no charge?

• Proton

• Electron

• Neutron

• Positron

Answer explanation

The neutron is a subatomic particle found in the nucleus of an atom and has no electric charge, unlike protons (positive charge) and electrons (negative charge). Therefore, the correct answer is the neutron.

What is the charge of a proton?

• +1.602 × 10⁻¹⁹ C

• -1.602 × 10⁻¹⁹ C

• 0 C

• +9.109 × 10⁻³¹ C

Answer explanation

The charge of a proton is +1.602 × 10⁻¹⁹ C, which is a fundamental constant in physics. This positive charge is essential for the stability of atoms and distinguishes protons from electrons, which have a negative charge.

Which subatomic particle has the smallest mass?

• Proton

• Neutron

• Electron

• Nucleus

Answer explanation

The electron has the smallest mass among subatomic particles, significantly lighter than protons and neutrons. While protons and neutrons are roughly equal in mass, electrons are about 1/1836 of a proton's mass.

What is the mass of an electron in kilograms?

• 1.672 × 10⁻²⁷ kg

• 1.675 × 10⁻²⁷ kg

• 9.109 × 10⁻³¹ kg

• 1.0073 kg

Answer explanation

The mass of an electron is approximately 9.109 × 10⁻³¹ kg, making it the correct choice among the options provided. The other values listed are incorrect for the mass of an electron.

Which of the following correctly describes isotopes?

• Same number of protons, different number of neutrons

• Same number of neutrons, different number of protons

• Same number of protons and neutrons

• Different numbers of protons and neutrons

Answer explanation

Isotopes are variants of the same element that have the same number of protons but different numbers of neutrons. This means they have the same atomic number but different atomic masses, making the first choice correct.

What is the atomic number of a ¹⁴₆C isotope?

• 14

• 6

• 8

• 20

Answer explanation

The atomic number of an element is defined by the number of protons in its nucleus. For the isotope ¹⁴₆C, the subscript '6' indicates it has 6 protons, making the correct answer 6.

Which of the following particles is responsible for the chemical behavior of an atom?

• Proton

• Neutron

• Electron

• Nucleus

Answer explanation

The electron is the particle responsible for the chemical behavior of an atom. It is involved in forming bonds and determining how atoms interact with each other, while protons and neutrons primarily contribute to the nucleus and atomic mass.

Which scientist proposed the "plum pudding" model of the atom?

• Bohr

• Rutherford

• Thomson

• Millikan

Answer explanation

The "plum pudding" model of the atom was proposed by J.J. Thomson in 1904. This model suggested that atoms are composed of a positively charged 'pudding' with negatively charged 'plums' (electrons) embedded within it.

What is the relative mass of a neutron in atomic mass units (amu)?

• 1.0073 amu

• 1.0087 amu

• 0.0005486 amu

• 1.6726 amu

Answer explanation

The relative mass of a neutron is approximately 1.0087 amu. This value is slightly higher than that of a proton, which is about 1.0073 amu, reflecting the neutron's additional binding energy in the nucleus.