sci_chem
Atomic Structure
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
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Chemistry · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
Protons (+1) and neutrons (0) sit in the nucleus. Electrons (-1) orbit it in shells.
The atomic number (Z) names the element. Neutrons = mass number (A) minus Z.
Most passed through, a few bounced back. So a tiny, dense, positive nucleus must sit at the centre.
The outer-shell (valence) electrons decide how an atom bonds and reacts.
Hard words & meanings
| proton | a positive particle (+1) in the nucleus with relative mass 1 |
| neutron | an uncharged particle in the nucleus with relative mass 1 |
| electron | a negative particle (-1) of negligible mass orbiting in shells |
| nucleus | the tiny dense positive centre holding protons and neutrons |
| atomic number | the number of protons in an atom; it identifies the element |
| mass number | the total number of protons and neutrons in the nucleus |
| isotope | atoms of one element with the same protons but different neutrons |
| electronic configuration | the arrangement of electrons in shells, e.g. 2, 8, 1 |
Model exam answers, grammar & audio
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