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प्रश्न
Select the correct answer from the options given below.
It is a metal in period 2 having electronic configuration 2, 1?
विकल्प
Beryllium
Lithium
Sodium
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उत्तर
Lithium
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संबंधित प्रश्न
Taking the example of an element of atomic number 16, explain how the electronic configuration of the atom of an element relates to its position in the modern periodic table and how valency of an element is calculated on the basis of its atomic number.
The elements 4Be, 12Mg and 20Ca, each having two valence electrons in their valence shells, are in periods 2, 3 and 4 respectively of the modern periodic table. Answer the following questions associated with these elements, giving reason in each case:
(a) In which group should they be?
(b) Which one of them is least reactive?
(c) Which one of them has the largest atomic size?
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modern periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.
Define the term : Valency
Write any one difference in the electronic configurations of group-1 and group-2 elements ?
Consider two elements 'X' (Atomic number 17) and 'Y' (Atomic number 20)
(i) Write the positions of these elements in the modern periodic table giving justification.
(ii) Write the formula of the compound formed by the combination of 'X' and 'Y'.
(iii) Draw the electron-dot structure of the compound formed and state the nature of the bond formed between the two elements ?
Which element has a total of three shells, with four electrons in its valence shell?
Which of the following is the valence shell for the elements of second period of the modern periodic table?
(a) M shell
(b) K shell
(c) L shell
(d) N shell
Select the correct answer
Most reactive character among the elements given below is found in
An element A has 2 electrons in its fourth shell. State:
position in the periodic table
