Practice free Atoms (Physics) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
What is the approximate size of the nucleus in Rutherford's model compared to the size of the atom?
The NCERT summary states, 'In Rutherford’s model, most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus (typically one by ten thousand the size of an atom)'.
Which atomic model suggested that the electrons and nucleus are held together by electrostatic forces of attraction?
Under Rutherford's nuclear model description in NCERT, point (iii) states: 'Electrons and the nucleus are held together by electrostatic forces of attraction.'
The discovery of sub-atomic particles eventually led to the proposal of various atomic models, including those by Thomson and Rutherford. Which statement about the divisibility of atoms is most accurate given this context?
The NCERT text states, 'Towards the end of the nineteenth century, it was proved experimentally that atoms are divisible and consist of three fundamental particles: electrons, protons and neutrons.' This led to the need for atomic models like Thomson's and Rutherford's.
Why did Rutherford's model face difficulty in explaining the stability of an atom?
The NCERT highlights this as a major difficulty: 'It predicts that atoms are unstable because the accelerated electrons revolving around the nucleus must spiral into the nucleus. This contradicts the stability of matter.'
Which of the following principles/concepts was ignored by Bohr's model, leading to its fundamental limitations?
The context states: 'This is not possible according to the Heisenberg uncertainty principle. Bohr model of the hydrogen atom, therefore, not only ignores the dual behaviour of electron but also contradicts Heisenberg uncertainty principle.'
Bohr's model struggled to explain the behavior of atoms in the presence of external fields. Which of the following effects directly demonstrates this limitation?
The context mentions: 'It was also unable to explain the splitting of spectral lines in the presence of magnetic field (Zeeman effect) or an electric field (Stark effect).'
Classical mechanics, based on Newton's laws, fails when applied to microscopic objects due to its ignorance of:
The context states: 'However it fails when applied to microscopic objects like electrons, atoms, molecules etc. This is mainly because of the fact that classical mechanics ignores the concept of dual behaviour of matter especially for sub-atomic particles and the uncertainty principle.'
The advent of quantum mechanics was crucial because it incorporated which of the following ideas to provide a more accurate description of atomic structure?
The context states: 'In fact an insight into the structure of the atom was needed which could account for wave-particle duality of matter and be consistent with Heisenberg uncertainty principle. This came with the advent of quantum mechanics.'
According to the provided text, what specific feature of electron description in Bohr's model is inconsistent with the Heisenberg Uncertainty Principle?
The context notes: 'An orbit is a clearly defined path and this path can completely be defined only if both the exact position and the exact velocity of the electron at the same time are known. This is not possible according to the Heisenberg uncertainty principle.'
Bohr's model is applicable only to 'hydrogenic' atoms. What is a key characteristic that defines a hydrogenic atom in this context?
The context defines it: '*Hydrogenic atoms are the atoms consisting of a nucleus with positive charge +Ze and a single electron, where Z is the proton number. Examples are hydrogen atom, singly ionised helium, doubly ionised lithium, and so forth. In these atoms more complex electron-electron interactions are nonexistent.'
Ready to ace NEET?
Free access · No credit card required
Yes. You can attempt every Atoms question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.
No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.
The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.