Chapter 4, Problem 36A

State the main points of Dalton’s atomic theory usingyour own words. Which parts of Dalton’s theory werelater found to be erronous? Explain why.

Interpretation Introduction

Interpretation:

The main points of Dalton’s atomic theory are to be written. Also, the parts of Dalton’s theory that were later proved wrong are to be discussed with reason.

Concept introduction:

Any substance that has mass and occupies space by having a fixed volume is matter. Everything that exists is a matter, table, chair, coins, etc. Atomic theories state that all the matter is composed of atoms that are composed of protons, neutrons and electrons.

Answer to Problem 36A

Dalton postulated that atom is the building block of matter and atom. It is indivisible and every atom of an element has the same properties. However, later it was proved that atom can be divided into subatomic particles and different atoms of the same element may have different masses.

Explanation of Solution

Dalton’s theory of atoms states that:

• Atom is the smallest component of the substance that binds together to form matter.

• Atom can neither be created nor be destroyed into further parts.

• All the atoms of the same elements have the same size, mass and chemical properties.

• Atoms of one element are different from the atoms of other elements.

• Chemical reactions cause atoms to separate from each other or to combine.

The points that were erroneous in Dalton’s atomic theory were:

• Atoms are indivisible, but it was later observed that atoms are divisible into several subatomic particles.
• Also, the point that all atoms of a given element have identical properties was proved wrong as atoms of the same element can have slightly different masses.

Conclusion

Dalton’s atomic theory states that all matter is composed of tiny particles called atom. It can neither be created nor be destroyed.