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प्रश्न
In terms of electronic configurations, explain the variation in the size of the atoms of the elements belonging to the same period and same group ?
उत्तर
The size of the atom increases on moving from top to bottom in the same group because at every step, new shells of electrons are added.
In a period, the size of the atom decreases on moving from left to right. This is because the atomic number of the elements increases on moving from left to right. Thereby, the number of electrons and protons also increases. Due to the increment in the number of protons, the nuclear charge also increases and the electrons get held more tightly to the nucleus.
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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.
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.
Which element has the electronic configuration 2, 8, 2?
Rewrite the following statement after correction, if necessary:
The metallic character of elements in a period increases gradually on moving from left to right.
How does the size of atoms (atomic size) generally vary in going from left to right in a period of the periodic table? Why does it vary this way?
Name two properties of elements whose magnitudes change when going from top to bottom in a group of the periodic table. In what manner do they change?
An element has 2 electrons in its N shell.
State the name assigned to this group.
What is the common feature of the electronic configuration of the elements at the end of period 2, and period 3?
What is modern periodic law?
Chlorine in the Periodic Table is surrounded by the elements with atomic number 9, 16, 18 and 35.
Which of these have Physical and Chemical properties resembling chlorine?
