Ch 03 - ATOMS AND MOLECULES9th Science
Early Philosophers of Matter: Indian & Greek Perspectives
How did ancient Indian and Greek philosophers conceptualize the ultimate indivisible particles of matter?
How did ancient Indian and Greek philosophers conceptualize the ultimate indivisible particles of matter?
Indian Philosophers:
- Maharishi Kanad (~500 BC) postulated that continuous division of matter (padarth) eventually yields indivisible particles he called Parmanu.
- Pakudha Katyayama elaborated that these Parmanu typically exist in a combined form, creating various types of matter.
Greek Philosophers:
- Around the same era, Democritus and Leucippus proposed a similar theory, stating matter divided continuously reaches an indivisible stage.
- Democritus coined the term atoms (from Greek atomos, meaning 'indivisible').
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John Dalton's Background
What was John Dalton's professional and personal background before he presented his paradigm-shifting atomic theory in 1808?
What was John Dalton's professional and personal background before he presented his paradigm-shifting atomic theory in 1808?
Early Life & Career:
- Born into a poor weaver's family in England in 1766.
- He began his career as a teacher at the unusually young age of twelve.
- Seven years later, he became a school principal at age nineteen.
- In 1793, he moved to Manchester to spend most of his life teaching and researching mathematics, physics, and chemistry in a college.
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Dalton's Atomic Theory: Core Postulates
What are the six core postulates of Dalton's Atomic Theory regarding the nature of elements and compound formation?
What are the six core postulates of Dalton's Atomic Theory regarding the nature of elements and compound formation?
Core Postulates:
- All matter is made of extremely tiny particles called atoms.
- Atoms are indivisible particles, which cannot be created or destroyed in a chemical reaction (explains Law of Conservation of Mass).
- Atoms of a given element are identical in mass and chemical properties.
- Atoms of different elements have different masses and chemical properties.
- Atoms combine in the ratio of small whole numbers to form compounds.
- The relative number and kinds of atoms are constant in a given compound (explains Law of Constant Proportions).
Prism Memory Hook
PIM-DSC: Particles (Atoms), Indivisible, Mass (Identical for same), Different for others, Small whole numbers, Constant relative number.
Also in this chapter
29 more cards to study in Prism
- 4Drawbacks of Dalton's Atomic Theory
- 5Law of Conservation of Mass
- 6Atomic Size (Radius)
- 7Law of Constant Proportions
- 8Origins & Rules of IUPAC Chemical Symbols
- 9Latin Derivations of Chemical Symbols
- 10The Initial Oxygen-16 Standard
- 11Unified Atomic Mass Unit (u)
- 12Molecules: Elements vs Compounds
- 13Atomicity of Elements
- 14Ions: Cations vs Anions
- 15Formula of Aluminium Oxide
- 16Polyatomic Ions
- 17Formula of Ammonium Sulphate
- 18Variable Valency in Transition Metals
- 19The Octopus Analogy for Valency
- 20Rules for Writing Chemical Formulae
- 21Avogadro's Number
- 22Calculating Moles from Given Mass
- 23Calculating Moles from Number of Particles
- 24Calculating Number of Atoms from Mass
- 25Mass Terminology: Molecular vs Formula Unit
- 26Calculating Molecular Mass: Nitric Acid
- 27Gram Atomic and Molecular Mass
- 28The Mole Concept
- 29Atomic & Molecular Radii
- 30Verification of Conservation of Mass
- 31Formula of an Unknown Element
- 32Calculating Ratio by Number of Atoms
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