* collect the
information of historical development
scientists
who developed the
and about
the
ATOMIC
THEORY.
Answers
Answer:
John Dalton (1766-1844) is the scientist credited for proposing the atomic theory.
Explanation:
It was the English chemist, John Dalton, who put the pieces of the puzzle together and developed an atomic theory in 1803.
Dalton's atomic theory contains five basic assumptions:
= All matter consists of tiny particles called atoms. Dalton and others imagined the atoms that composed all matter as tiny, solid spheres in various stages of motion.
= Atoms are indestructible and unchangeable. Atoms of an element cannot be created, destroyed, divided into smaller pieces, or transformed into atoms of another element. Dalton based this hypothesis on the law of conservation of mass as stated by Antoine Lavoisier and others around 1785.
= Elements are characterized by the weight of their atoms. Dalton suggested that all atoms of the same element have identical weights. Therefore, every single atom of an element such as oxygen is identical to every other oxygen atom. However, atoms of different elements, such as oxygen and mercury, are different from each other.
= In chemical reactions, atoms combine in small, whole-number ratios. Experiments that Dalton and others performed indicated that chemical reactions proceed according to atom to atom ratios which were precise and well-defined.
= When elements react, their atoms may combine in more than one whole-number ratio. Dalton used this assumption to explain why the ratios of two elements in various compounds, such as oxygen and nitrogen in nitrogen oxides, differed by multiples of each other.
John Dalton's atomic theory was generally accepted because it explained the laws of conservation of mass, definite proportions, multiple proportions, and other observations.