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प्रश्न
State the number of elements in period 1, period 2 and period 3 of the periodic table.
उत्तर
Number of elements in period 1 = 2
In period 2 = 8
In period 3 = 8.
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संबंधित प्रश्न
How do the atomic size and metallic character of elements vary as we move :-
(a) down a group and
(b) from left to right in a period
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Differentiate between Normal elements and Transition elements.
How does the tendency to gain electrons change as we go down in group 17 of the periodic table? Why does it change this way?
An element 'X' (Atomic number – 20) burns in the presence of oxygen to form a basic oxide.
(a) Identify the element and write its electronic configuration.
(b) State its group number and period number in the Modern Periodic Table.
(c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.
On the basis of electronic configuration, how will you identify the first and the last element of a period?
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Parts (i) to (v) refer to changes in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d).
(i) The non metallic character of the elements:
(a) Decreases
(b) Increases
(c) Remains the same
(d) Depends on the period
(ii) The electro negativity
(a) Depends on the number of valence electrons
(b) Remains the same
(c) Decreases
(d) Increases
(iii) The ionization potential
(a) Goes up and down
(b) Decreases
(c) Increases
(d) Remains the same
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(a) Decreases
(b) Increases
(c) Remains the same
(d) Sometimes increases and sometimes decreases
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(a) Goes up and down
(b) Decreases and then increases
(c) Increases
(d) decreases
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