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प्रश्न
State the meaning of the term – (a) atom, (b) molecule, (c) radical – with a suitable example.
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उत्तर
(a) Atom: It is the smallest particle of an element, which is made up of only one kind of atom. Atoms are built up of sub-atomic particles protons, neutrons, and electrons.
Example: O - Oxygen atom, H - Hydrogen atom
(b) Molecule: “The smallest particle of a substance which can exist on its own and retains the physical and chemical properties of the substance is called a molecule.”
Example: O2 - Oxygen molecule, H2O - Water molecule
(c) Radical: A radical is an atom of an element or a group of atoms of different elements that behaves as a single unit with a positive or negative charge on it.
Example: \[\ce{NH^+4}\] - Ammonium radical
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Project.
To have an idea of what atoms are, students can be asked to construct atoms using pipe cleaners (thin metal wires-electron shells), pompoms (balls-different colours for protons and neutrons) and beads (electrons). Students will love and enjoy putting them together and they look great hanging from the ceiling in the classroom.
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