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प्रश्न
Answer the following question.
Define the atomic size. Give its unit of measurement. In the modern periodic table what trend is observed in the atomic radius in a group and a period and why is it so?
उत्तर
Atomic size is the distance between the center of an atom i.e. from the nucleus to the outermost shell (valence shell) of that atom.
Atomic size is measured in Angstroms (A), where 1 Angstrom = 10-10 meters.
In the modern periodic table, the atomic size of elements increases down the group and the atomic size decrease along the period from left to right.
Down the group, as the number of energy shells of the atoms keeps on increasing from top to bottom so, the atomic radius also increases.
During the period, the atomic number of elements increases which leads to an increase in the number of protons inside the nucleus and thus, the effective nuclear charge increases. So, the atomic radius decreases over the period.
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संबंधित प्रश्न
Give two example of group 17 elements.
The atomic particle whose number in the atoms of an element always remains the same and which forms the real basis for the modern classification of elements is:
(a) electron
(b) proton
(c) neutron
(d) meson
How would the tendency to lose electrons change as we go from left to right across a period of the periodic table?
Explain why All the elements of a period have different chemical properties.
What is a period in a periodic table?
How many groups and periods does the modern periodic table have?
An element E has following electronic configuration:
|
K |
L |
M |
|
2 |
8 |
6 |
(a) To which group of the periodic table does element E belong?
(b) To which period of the periodic table does element E belong?
(c) State the number of valence electrons present in element E.
(d) State the valency of the element E.
Give the symbol and valency of the following element and radical.
Ammonium
Give the chemical formula of sodium hydroxide
Select the appropriate options and complete the following paragraph:
(metals, non-metals, metalloids, four, seven, s-block, p-block, d-block, f-block).
On the basis of electronic configuration, elements in the modern periodic table are classified Into ______ blocks. Groups 1 and 2 elements are included in ______ and all these elements are metals. (except Hydrogen). Group 13 to 18 elements are included in ______. This block contains metals, non-metals and metalloids. Group 3 to 12 elements are included in ______ and all the elements are ______ elements shown at the bottom of the periodic table i.e. Lanthanides and Actinides constitute ______ and all these elements are metals.
