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(a) Lithium, sodium, potassium are all m...

(a) Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?
(b) Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?

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(a) Yes, The atoms of all the three elements lithium, sodium, and potassium have one electron in their outermost shells.
(b) Both helium (He) and neon (Ne) have filled outermost shells. Helium has aduplet in its K shells, while neon has an octet in its L shell.
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NCERT ENGLISH-PERIODIC CLASSIFICATION OF ELEMENTS-Exercise
  1. Use Mendeléev’s Periodic Table to predict the formulae for the oxides ...

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  2. Besides gallium, which other elements have since been discovered that ...

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  3. What were the criteria used by Mendeléev in creating his Periodic Tabl...

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  4. Why do you think the noble gases are placed in a separate group?

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  5. How could the Modern Periodic Table remove various anomalies of Mendel...

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  6. Name two elements you would expect to show chemical reactions similar ...

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  7. Name (a) three elements that have a single electron in their outermo...

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  8. (a) Lithium, sodium, potassium are all metals that react with water to...

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  9. In the Modern Periodic Table, which are the metals among the first ten...

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  10. By considering their position in the Periodic Table, which one of the ...

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  11. Which of the following statements is not a correct statement about the...

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  12. Element X forms a chloride with the formula XCl(2), which is a solid w...

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  13. Which element has (a) two shells, both of which are completely filled...

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  14. (a) What property do all elements in the same column of the Periodic T...

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  15. An atom has electronic configuration 2, 8, 7. (a) What is the atomic n...

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  16. The position of three elements A, B and C in the Periodic Table are sh...

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  17. Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to...

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  18. How does the electronic configuration of an atom relate to its positio...

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  19. In the Modern Periodic Table, calcium (atomic number 20) is surrounded...

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  20. Compare and contrast the arrangement of elements in Mendeléev’s Period...

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