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Both helium (He) and magnesium (Mg) have...

Both helium (He) and magnesium (Mg) have two valence electrons. He represents a noble gas element, but Mg does not. Assign reason.

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To understand why helium (He) is a noble gas while magnesium (Mg) is not, despite both having two valence electrons, we can analyze their electronic configurations step by step. ### Step 1: Write the electronic configuration of Helium (He) - Helium has an atomic number of 2, which means it has 2 electrons. - The electronic configuration of helium is: - K-shell: 2 electrons - Therefore, the configuration can be written as: **1s²** ...
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Both helium (He) and beryllium (Be) have two valence electrons.Whereas he represent a noble gas element,Be does no. Assign reason.

Na, Mg and Al are the elements having one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive ? Justify your answer stating reason for each.

Knowledge Check

  • All alkali metals have one valence electron, ns^(1) , outside the noble gas core except :

    A
    Na
    B
    Fr
    C
    Cs
    D
    None of these

  • Most of the monatomic ions of the representative elements are obtained by removing all the valence electrons from the atoms of metallic elements. Once these atoms have lost their valence electrons, they have stable noble gas or pseudo noble gas configurations. Which of these elements forms a cation having pseudo noble gas configuration?

    A
    `Mg`
    B
    `Ga`
    C
    `K`
    D
    `Al`

  • Assertion : Nitride ion (N^(3-)) and magnesium ion (Mg^(2+)) are both isoelectronic species. Reason : the charge on nitride is different from Mg^(2+) ion.

    A
    If both assertion and reason are correct and reason is correct explanation for assertion.
    B
    If both assertion and reason are correct but reason is not correct explanation for assertion.
    C
    If assertion is correct but reason is incorrect.
    D
    If both assertion and reason are incorrect.

    • Similar Questions

    Explore conceptually related problems

    Both helium and beryllium have ns^(2) valence electronic configuration. However, beryllium forms compounds and helium cannot form compounds. Explain.

    Na, Mg and Al are the elements of the same period of Modern Periodic Table having one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each case.

    Assertion : The number of electrons gained, lost or shared by the atom of an element so as to complete its octet is called the valency of the element. Reason : Elements having the same number of valence electrons in their atoms possess different chemical properties.

    Helium is a noble gas with 2 electrons in its outermost shell. Its valency is 0.

    Name: (i) three elements that have only a single electron in their outermost shells. (ii) two elements that have two electrons in their valence shells. (iii) three elements with completely filled outermost shells.

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