ATOMS AND MOLECULES
Atoms as the building blocks of matter, made up of electrons, protons, and
neutrons.
Molecules formed by chemically bonded atoms.
The Law of Conservation of Mass proposed by Antoine Lavoisier in 1789.
An example of this law with the decomposition of calcium carbonate into
calcium oxide and carbon dioxide, showing mass conservation (100g
reactant = 100g products).
Here's the text from the image:
→ Acc to this law Matter up neither be created nor be destroyed in a Chemical
reaction
Reactants :- The Substance Combines
Product :- The substance produced
Dalton atomic theory
Matter can't be created or destroyed in a chemical reaction 🔄.
Reactants combine to form products 🧬.
Dalton's atomic theory says every element is made of small particles called
atoms ⚛️.
Atoms of the same element are identical in mass and properties 🔩.
Atoms can't be created or destroyed 🚫.
Drawbacks of Dalton’s Atomic Theory
1. Atoms are NOT indivisible – Discovery of subatomic particles (electrons,
protons, neutrons) proved atoms can be split.
2. Isotopes – Dalton assumed all atoms of an element have identical mass, but
isotopes with different masses exist
3. Fails for non-stoichiometric compounds – Some compounds have variable
composition (berthollides), contradicting fixed atom ratios.
4. No explanation of chemical bonding – It didn’t explain why atoms combine or
how electrons are shared/ transferred.
5. Ignores isotopes & atomic weights – Modern relative atomic masses are
averages of isotopes, not whole numbers as Dalton suggested. molecule is a
group of two or more atoms chemically bonded together, forming the
Atoms as the building blocks of matter, made up of electrons, protons, and
neutrons.
Molecules formed by chemically bonded atoms.
The Law of Conservation of Mass proposed by Antoine Lavoisier in 1789.
An example of this law with the decomposition of calcium carbonate into
calcium oxide and carbon dioxide, showing mass conservation (100g
reactant = 100g products).
Here's the text from the image:
→ Acc to this law Matter up neither be created nor be destroyed in a Chemical
reaction
Reactants :- The Substance Combines
Product :- The substance produced
Dalton atomic theory
Matter can't be created or destroyed in a chemical reaction 🔄.
Reactants combine to form products 🧬.
Dalton's atomic theory says every element is made of small particles called
atoms ⚛️.
Atoms of the same element are identical in mass and properties 🔩.
Atoms can't be created or destroyed 🚫.
Drawbacks of Dalton’s Atomic Theory
1. Atoms are NOT indivisible – Discovery of subatomic particles (electrons,
protons, neutrons) proved atoms can be split.
2. Isotopes – Dalton assumed all atoms of an element have identical mass, but
isotopes with different masses exist
3. Fails for non-stoichiometric compounds – Some compounds have variable
composition (berthollides), contradicting fixed atom ratios.
4. No explanation of chemical bonding – It didn’t explain why atoms combine or
how electrons are shared/ transferred.
5. Ignores isotopes & atomic weights – Modern relative atomic masses are
averages of isotopes, not whole numbers as Dalton suggested. molecule is a
group of two or more atoms chemically bonded together, forming the
