Atomic Models, Ions, Isotopes, Lewis D., Electron configuration

Which of the following experiments proved that most of the atom is empty space?

• Cathode ray tube experiment

• Rutherford’s gold foil experiment

• Bohr's hydrogen emission spectrum

• Millikan’s oil drop experiment

According to the quantum mechanical model, where are electrons most likely to be found?

• In fixed orbits around the nucleus

• Inside the nucleus

• In electron clouds or orbitals

• On the surface of the atom

What was the key discovery in J.J. Thomson’s cathode ray experiment?

• Neutrons

• Protons

• Electrons

• Nucleus

In Bohr's model, what happens when an electron moves from a lower to a higher energy level?

• The atom becomes unstable

• The electron loses energy

• The electron absorbs energy

• The nucleus loses protons

What feature of the atom did John Dalton’s model fail to explain?

• Atoms can be divided into smaller particles

• The existence of chemical bonds

• The presence of different isotopes

• That all atoms of an element are identical

Which element is more likely to form a cation?

• Fluorine

• Neon

• Sodium

• Sulfur

What charge does an oxygen ion (O²⁻) have after gaining 2 electrons?

• +2

• -1

• -2

• 0

Which of the following ions has gained an electron?

• Na⁺

• Cl⁻

• Mg²⁺

• He

True or False: Ions with opposite charges attract each other to form ionic compounds.

• True

• False

Which ion is likely to form when magnesium (Mg) loses two electrons?

• Mg⁺

• Mg²⁺

• Mg⁻

• Mg²⁻