Home
Class 11
CHEMISTRY
The ions of NaF and MgO have the same nu...

The ions of NaF and MgO have the same number of electrons and inter nuclear distances are about the same (235 pm and 215 pm). Why are then the melting points of NaF and MgO so different `(992^(@)C and 2642^(@)C)`?

Text Solution

Verified by Experts

In `Mg^(2+)O^(2-)` , both the ions carry two units of charge whereas in `Na^+ F^-` , each ion carries only one unit charge. Hence, electrostatic forces of attraction in MgO are stronger.
Promotional Banner

Topper's Solved these Questions

  • STATES OF MATTER: SOLID MATTER

    PRADEEP|Exercise ANALYTICAL (PROBLEMS )|11 Videos

  • STATES OF MATTER: SOLID MATTER

    PRADEEP|Exercise COMPETITION FOCUS (I.MULTIPLE CHOICE)|52 Videos

  • STATES OF MATTER: SOLID MATTER

    PRADEEP|Exercise ADDITIONAL QUESTIONS ( LONG ANSWER )|9 Videos

  • STATES OF MATTER : GASES AND LIQUIDES

    PRADEEP|Exercise VIII. ASSERTION-REASON TYPE QUESTIONS (TYPE-II)|12 Videos

  • STRUCTURE OF ATOM

    PRADEEP|Exercise Competition Focus (JEE (Main and Advanced)/Medical Entrance (IX. Assertion And Reason Type Questions (Type II))|12 Videos

Similar Questions

Explore conceptually related problems

Why the melting points of NaF and MgO (990^(@)C and 2640^(@)C ) are so different although both have same number of electrons and nearly the same internuclear distance (236 pm and 216 pm)?

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of elements D is almost neutral. Which one of the following will have largest atomic radii?

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of element D is almost neutral. Which one of the eight elements would have the largest atomic radius?

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of element D is almost neutral. To which group or period of the periodic table do the elements A and B belong?

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of elements D is almost neutral. Which of the following is likely to be halogen?

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of elements D is almost neutral. To which period the listed elements belong?

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of elements D is almost neutral. Which one of the following elements is likely to be a noble gas?

Q 4 Two atoms are said to be isobars if. * (a) they have same atomic number but different mass number. (b) they have same number of electrons but different number of neutrons (c) they have same number of neutrons but different number of electrons. (d) sum of the number of protons and neutrons is same but the number of protons is different.

PRADEEP-STATES OF MATTER: SOLID MATTER-ANALYTICAL (QUESTION)
  1. Why ureas has a sharp melting point but glass does not ?

    Text Solution

    |

  2. The mineral haematite, Fe(2)O(3) consists of a cubic close packed ar...

    Text Solution

    |

  3. Zine oxide is white but it turns yellow on heating . Explain.

    Text Solution

    |

  4. Why does zinc oxide exhibit enhanced electrical conducity on heating ?

    Text Solution

    |

  5. The electrical conductivity of a metal decreases with rise in temperat...

    Text Solution

    |

  6. The ions of NaF and MgO have the same number of electrons and inter nu...

    Text Solution

    |

  7. Diamond and solid rhombic sulphur both are covalent solids but the lat...

    Text Solution

    |

  8. NaCl and CsCl have similar formular . Then why they have differnet st...

    Text Solution

    |

  9. Why is coordination number of 12 not found in lonic crystals ?

    Text Solution

    |

  10. Analyses shows that FeO has a non-stoichiometric composition with form...

    Text Solution

    |

  11. ZnO crystals on heating acquires the formuls Zn(1+x)O. Or There is...

    Text Solution

    |

  12. If the atoms of an element have the radius r, then in a primitive cubi...

    Text Solution

    |

  13. Out of NaCl and CsCl , which one is more stable and why ?

    Text Solution

    |

  14. In a crystal, Frenkel defect is not shown by alkali metal halides but ...

    Text Solution

    |

  15. What is the arrangement of atoms in the lattice structure of diamond a...

    Text Solution

    |

  16. The figures given below show the location of atoms in three crystallog...

    Text Solution

    |

  17. r(Na^(+))" and " r(Cl^(-)) represent radius of Na^(+) and Cl^(-) ions ...

    Text Solution

    |