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प्रश्न
Why do elements in the same group show similar properties but the elements in different groups show different properties?
उत्तर
The properties of an element depends on the number of valence electrons present in an atom of the element. Elements of a particular group have similar electronic configurations and the same number of valence electrons in their atoms. Hence, all the elements belonging to a certain group show similar properties. However, the electronic configurations of elements change on moving from left to right in a periodic table. Different groups have different valencies. Therefore, elements in different groups show different properties.
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संबंधित प्रश्न
The position of eight elements in the Modern Periodic Table is given below where atomic numbers of elements are given in the parenthesis.
| Period No. | ||
| 2 | Li(3) | Be(4) |
| 3 | Na(11) | Mg(12) |
| 4 | K(19) | Ca(20) |
| 5 | Rb(37) | Sr(38) |
(i) Write the electronic configuration of Ca.
(ii) Predict the number of valence electrons in Rb.
(iii) What is the number of shells in Sr?
(iv) Predict whether K is a metal or a non – metal.
(v) Which one of these elements has the largest atom in size?
(vi) Arrange Be, Ca, Mg and Rb in the increasing order of the size of their respective atoms.
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
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
Which of the following set of elements is written correctly in the order of their increasing metallic character?
(a) Mg, Al, Si
(b) C, O, N
(c) Na, Li, K
(d) Be, Mg, Ca
State the number of elements in period 1, period 2 and period 3 of the periodic table.
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
Place the three elements fluorine, beryllium and nitrogen in the order of increasing electronegativity.
With reference to the variation of properties in the Periodic table, which of the following is generally true?
Name and state the following with reference to the elements of the first three periods of the periodic table.
Alkaline earth metal in period 3.
Based on the group valency of element write the molecular formula of the following compound giving justification:
Halide of the elements of group thirteen
Write the electronic configuration of two elements A and B whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element A reacts with element B. State whether this compound is acidic, basic or neutral. Give a reason to justify your answer.
