3 Isotopes are atoms of the same element having: A Different atomic numbers B Different mass numbers C Different protons D Different electrons
5 Samir is learning about carbon dating. He discovers that it is used to determine the age of ancient artifacts. Which isotope is used in carbon dating? A Carbon-12 B Carbon-13 C Carbon-14 D Carbon-15
9 Samir is learning about cations. He knows that sodium forms a cation with a +1 charge. How does sodium achieve this charge? A By gaining one electron B By losing one electron C By gaining one proton D By losing one proton
10 Xia is studying the history of atomic models. She learns that the quantum mechanical model is based on the wave-particle duality of electrons. Who proposed this concept? A Erwin Schrödinger B Niels Bohr C Ernest Rutherford D John Dalton
12 Hannah is studying the determination of relative atomic mass. She knows that it is calculated using the masses of isotopes and their abundances. What is the formula used? A Average mass = sum of masses of all atoms / number of atoms B Relative atomic mass = Σ (isotope mass × fractional abundance) C Relative atomic mass = mass of isotope × 12 D Relative atomic mass = number of protons + neutrons
14 Carlos is analyzing the defects of Bohr's atomic model. He learns that Bohr's model could not explain the spectra of atoms with more than one electron. What is the main reason for this defect? A It did not include neutrons B It assumed electrons move in fixed circular paths and did not account for electron-electron interactions C It placed electrons in random positions D It ignored the nucleus
16 Vera is studying shells and sub-shells. She learns that the second shell (n=2) has two sub-shells: s and p. How many electrons can the p sub-shell hold? A 2 B 6 C 10 D 14
17 The smallest particle of an element that retains its properties is: A Molecule B Atom C Ion D Electron
18 Bohr’s model explains: A Chemical bonding only B Atomic nucleus C Electron arrangement in shells D Neutron behavior
19 Energy of electrons increases as we move: A Toward nucleus B Away from nucleus C Inside nucleus D Between protons
20 According to Bohr, electrons move in: A Random paths B Fixed energy levels C Straight lines D Nucleus
21 Fatima is reviewing atomic structure and subatomic particles. She knows that electrons are found outside the nucleus. What is the approximate mass of an electron compared to a proton? A Approximately equal B About 1/1836 of a proton C Twice the mass of a proton D About 1/1000 of a proton
23 Rania is studying relative atomic mass. She learns that it is the weighted average mass of an atom compared to 1/12th of carbon-12. What unit is used for relative atomic mass? A Grams B Atomic mass unit (amu) C Kilograms D Moles
24 Julia is studying electronic configuration. She learns that electrons fill orbitals in a specific order. What is the order of filling according to the Aufbau principle? A 1s, 2s, 2p, 3s, 3p, 3d, 4s... B 1s, 2s, 2p, 3s, 3p, 4s, 3d... C 1s, 2p, 2s, 3s, 3p, 4s, 3d... D 1s, 2s, 3s, 2p, 3p, 4s, 3d...
25 George is learning about radioisotopes. He understands that some isotopes are used in medicine for diagnosis and treatment. Which radioisotope is commonly used in medical imaging? A Uranium-238 B Carbon-14 C Technetium-99m D Chlorine-37
26 The nucleus of an atom contains: A Only electrons B Protons and neutrons C Only neutrons D Only protons
28 Mohamed is learning about the nucleus. He understands that the nuclear force holds the nucleus together. Why is the nuclear force necessary? A To overcome the attractive force between protons and electrons B To overcome the repulsive electrostatic force between protons C To keep electrons in orbit D To separate neutrons from protons
30 Qasim is learning about isotopes of uranium. He learns that uranium-235 and uranium-238 are both isotopes. Which isotope is commonly used in nuclear reactors? A Uranium-238 B Uranium-235 C Uranium-236 D Uranium-239