Question

Explain and arrange the following statements in the correct chronological order to show how atomic models have evolved over time.

1. Bohr’s model proposed that electrons move in fixed orbits around the nucleus, each with a definite energy.
2. Thomson’s model depicted the atom as a 'plum pudding' with electrons embedded in a sphere of positive charge.
3. Rutherford's model proposed that atoms have a dense central nucleus.
4. Dalton’s model described atoms as indivisible particles.

Answer 1

1. Dalton’s Atomic Model (1803) - Dalton described atoms as tiny, indivisible particles that make up matter. 
2. Thomson’s Atomic Model (1904) - Thomson proposed the plum pudding model, in which electrons are embedded in a sphere of positive charge. 
3. Rutherford’s Atomic Model (1911) -  Rutherford proposed that an atom has a small, dense, positively charged nucleus at its centre, with electrons revolving around it. 
4. Bohr’s Atomic Model (1913) - Bohr proposed that electrons revolve around the nucleus in fixed orbits or energy levels without losing energy.