One of the important postulations of Dalton's atomic theory is:

Explanation:

John Dalton Postulates about atoms.

• All matter is made up of tiny, indivisible particles called atoms.
• All atoms of a specific element are identical in mass, size, and other properties. However, atoms of different element exhibit different properties and vary in mass and size.
• Atoms can neither be created nor destroyed. Furthermore, atoms cannot be divided into smaller particles.
• Atoms of different elements can combine with each other in fixed whole-number ratios in order to form compounds.
• Atoms can be rearranged, combined, or separated in chemical reactions

Important Points

John Dalton raised the atomic theory that acted as an explanation of the following two laws. 

• Law of conservation of mass:
  • According to the law, mass can neither be destroyed nor created in any chemical reaction.
• Law of constant proportion/ definite proportion:
  • The laws state that in a chemical substance, the elements are always present in certain proportions by mass.
• For example:
  • Oxygen & Hydrogen are present in water in a ratio of 8:1.
  • So we will obtain 1g of hydrogen and 8g of oxygen if we decompose 9g of water.
• Atom: 
  • An atom is the smallest invisible unit of matter that constitutes a chemical element.
  • Every plasma, solid, gas & liquid, composed of ionized or neutral atoms.
  • Around 100 picometers across, atoms are extremely small. 
• Atomic theory: 
  • John Dalton discovered atomic theory.
  • As per the theory, all matter whether it is a mixture, compound, element, is consists of invisible particles called ‘atoms’.