Question

what does the bohr model contribute to the theory on the structure of the atom? a electrons are arranged in specific energy levels around the atom. b atoms are made of electrons, protons, and neutrons. c valence electrons describe an atom’s reactivity. d atoms have a central positively charged nucleus.

Explanation:

• Option A: The Bohr model proposed that electrons orbit the nucleus in specific, quantized energy levels (shells), which is a key contribution to atomic structure theory.
• Option B: The discovery of protons, neutrons, and electrons as subatomic particles and their composition of atoms is from other atomic models/experiments, not the Bohr model.
• Option C: The concept of valence electrons and their relation to reactivity is not a core contribution of the Bohr model.
• Option D: The idea of a central positively charged nucleus was from Rutherford's model, not Bohr's.

Answer:

A. Electrons are arranged in specific energy levels around the atom.