Atomic Structure – Composition of Atoms Which statement best describes the basic composition of atoms in modern atomic theory?

Introduction / Context:
Atoms consist of a tiny, massive nucleus surrounded by a cloud of electrons. Recognising this structure is fundamental to chemistry, spectroscopy, and nuclear physics. This question asks you to pick the most accurate concise description.

Given Data / Assumptions:

• Nucleus contains protons (positive charge) and neutrons (neutral), together most of the mass.
• Electrons carry negative charge and occupy orbitals around the nucleus.
• We need a minimal but correct description.

Concept / Approach:
“Electrons and nuclei” accurately captures the two major components without listing substructure. Saying “electrons and protons” omits neutrons and misrepresents the nucleus. “Electrons only” or “protons only” are obviously incomplete. Thus, the best answer is the pair that partitions matter into its nuclear core and electronic cloud.

Step-by-Step Solution:

Verification / Alternative check:
Rutherford scattering and later experiments show a compact, heavy nucleus; spectral lines and quantum mechanics confirm bound electrons. These observations collectively support the nucleus–electron model.

Why Other Options Are Wrong:

• electrons and protons: Excludes neutrons; not the standard phrasing.
• electrons only / protons only: Discarded by basic evidence.

Common Pitfalls:
Forgetting neutrons because they carry no charge. Despite neutrality, they are essential to nuclear mass and stability, which is captured by the term “nucleus.”

Final Answer:
electrons and nuclei