Unit Test Part I

Which subatomic particle is negatively charged?

• Proton

• Neutron

• Electron

• Positron

Which particles are in the nucleus of an atom?

• Protons only

• Neutrons only

• Protons and neutron

• Proton and electrons

Who proposed the "Plum Pudding Model" of the atom?

• Niels Bohr

• John Dalton

• J. J. Thomson

• Ernest Rutherford

An atom of oxygen has an atomic number of 8 and a mass number of 16. How many neutrons does it have?

• 0

• 8

• 16

• 24

What charge does an ion have if it loses one electron?

• Neutral

• Positive

• Negative

• Unchanged

What are isotopes?

• Atoms with the same mass numbers

• Atoms with the same number of protons and neutrons

• Atoms with different numbers of protons and electrons

• Atoms with the same number of protons but different numbers of neutrons

What is the role of neutrons in the nucleus?

• To orbit the nucleus

• To provide a positive charge

• To balance the number of electrons

• To stabilize the nucleus by reducing proton repulsion

What was the primary observation from Rutherford's gold foil experiment?

• Alpha particles stuck to the foil

• Electrons were discovered in the nucleus

• All alpha particles were deflected at large angles

• Most alpha particles passed through the foil without deflection

Which paricle is the heaviest among the three subatomic particles?

• Proton

• Neutron

• Electron

• Positron

How does the mass of the nucleus compare to the rest of the atom?

• The nucleus is lighter and occupies less space

• The nucleus is heavier and occupies less space

• The nucleus is heavier and occupies most of the atom's space

• The nucleus is lighter and occupies most of the atom's space