MCQ Test PDF

Question 1: Which model proposed that atoms are solid spheres and indivisible? A) Plum Pudding Model B) Nuclear Model C) Solid Sphere Model D) Planetary Model Answer: C) Solid Sphere Model Explanation: John Dalton proposed the Solid Sphere Model in 1803, suggesting that atoms are indivisible soli...

Question 1: Which model proposed that atoms are solid spheres and indivisible? A) Plum Pudding Model B) Nuclear Model C) Solid Sphere Model D) Planetary Model Answer: C) Solid Sphere Model Explanation: John Dalton proposed the Solid Sphere Model in 1803, suggesting that atoms are indivisible solid spheres. --- Question 2: Who discovered the electron and proposed the Plum Pudding Model of the atom? A) John Dalton B) Niels Bohr C) J.J. Thomson D) Ernest Rutherford Answer: C) J.J. Thomson Explanation: J.J. Thomson discovered the electron in 1904 and proposed the Plum Pudding Model, which depicted the atom as a ball of positive charge with electrons embedded in it. --- Question 3: What was the signi cant nding of Ernest Rutherford's gold foil experiment? A) Atoms are indivisible B) Electrons orbit the nucleus in xed paths C) Most of the atom is empty space, with a central nucleus D) Atoms are solid spheres fi fi fi  Answer: C) Most of the atom is empty space, with a central nucleus Explanation: In 1911, Rutherford's gold foil experiment revealed that most of the atom is empty space and the positive charge is concentrated in a nucleus. --- Question 4: In which atomic model are electrons described as orbiting the nucleus at xed distances? A) Plum Pudding Model B) Nuclear Model C) Solid Sphere Model D) Planetary Model Answer: D) Planetary Model Explanation: Niels Bohr proposed the Planetary Model in 1913, where electrons orbit the nucleus in xed orbits or energy levels. --- Question 5: Which subatomic particle has a relative mass of 1 and no charge? A) Proton B) Neutron C) Electron D) Positron Answer: B) Neutron Explanation: Neutrons have a relative mass of 1 and no charge. They are found in the nucleus of atoms. --- fi fi Question 6: How is an ion formed? A) By gaining or losing protons B) By gaining or losing neutrons C) By gaining or losing electrons D) By splitting the nucleus Answer: C) By gaining or losing electrons Explanation: Ions are atoms that have either gained or lost electrons, resulting in a net charge. --- Question 7: What is the charge and relative mass of a proton? A) Charge: +1, Relative Mass: 1 B) Charge: -1, Relative Mass: 0 C) Charge: 0, Relative Mass: 1 D) Charge: -1, Relative Mass: 1 Answer: A) Charge: +1, Relative Mass: 1 Explanation: Protons have a positive charge (+1) and a relative mass of 1. They are located in the nucleus. --- Question 8: Which element's isotopes are used as an example in the context of approximately equal abundance in the mass spectrometry application? A) Chlorine B) Bromine C) Xenon D) Neon Answer: B) Bromine  Explanation: Bromine has two isotopes, 79Br and 81Br, which are approximately equal in abundance and often used to illustrate mass spectrometry principles. --- Question 9: What de nes a covalent bond? A) Complete transfer of electrons from one atom to another B) Sharing of electron pairs between two atoms C) Electrostatic attraction between cations and anions D) Attraction between metal ions and delocalized electrons Answer: B) Sharing of electron pairs between two atoms Explanation: A covalent bond involves the sharing of a pair of electrons between two atoms. This is common in non-metal atoms. --- Question 10: Which of the following correctly describes an alkaline earth metal in terms of ion formation according to Born-Haber cycles? A) Undergoes 1st I.E. to form 1+ ions B) Undergoes both 1st & 2nd I.E. stages to form 2+ ions C) Undergoes no ionization D) Forms covalent bonds only Answer: B) Undergoes both 1st & 2nd I.E. stages to form 2+ ions Explanation: Group 2 elements (alkaline earth metals) undergo rst and second ionization energies to form 2+ ions as part of Born-Haber cycles. fi fi