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प्रश्न
Name the elements in Period 1.
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उत्तर
Names of elements are (H) Hydrogen and Helium (He).
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संबंधित प्रश्न
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 : Atomic size
Why does the size of the atoms progressively become smaller when we move from sodium (Na) to chlorine (Cl) in the third period of the periodic table?
Five elements A, B, C, D and E have atomic numbers of 2, 3, 7, 10 and 18 respectively. The elements which belong to the same period of the periodic table are:
(a) A, B, C
(b) B, C, D
(c) A, D, E
(d) B, D, E
The element which has the maximum number of valence electrons is:
(a) Na
(b) P
(c) Si
(d) A
How do the following change on moving from left to right in a period of the periodic table?
Give examples in support of your answer.
atomic structure (electron arrangements) ?
State whether the following statement is true or false
On moving horizontally across a period, number of valence electrons increases from one to eight.
Explain, the statement 'In each period, the atomic radii gradually decrease with increase in atomic number'. Give one example to justify your answer.
Moving left to right in the second period, the number of valence electrons _____.
Electron Affinity is maximum in ______.
