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प्रश्न
The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm; 104 pm and 143 pm respectively. Giving a reason, arrange these elements in the increasing order of atomic numbers in the period.
उत्तर
The elements in the increasing order of atomic numbers in the period is X<Z<Y. On moving from left to right in a period, the atomic number increases. Hence, the size of the atomic radius decreases.
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संबंधित प्रश्न
Name the element that has two shells, both of which are completely filled with electrons.
An element X belongs to group 2 and another element Y belongs to group 15 of the periodic table:
(a) What is the number of valence electron in X?
(b) What is the valency of X?
(c) What is the number of valence electrons in Y?
(d) What is the valency of Y?
Explain how you have arrived at your answers.
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
In each of the following pair, choose the atom having the bigger size:
Na (At. No. 11) or K (At. No. 19)
State whether the following statement is true or false
On moving horizontally across a period, number of valence electrons increases from one to eight.
Name the elements in period 1.
The following table represents the first period of the modern periodic table. Study the table and answer the questions that follow:
(i) Write the formula of the sulphate of the element with atomic number 13.
(ii) What type of bonding will be present in the oxide of the element with atomic number 1?
(iii) Which feature of the atomic structure accounts for the similarities in the chemical properties of the elements in group VIIA of the periodic table?
(iv) Name the element which has the highest ionization potential.
(v) How many electrons are present in the valence shell of the element with atomic number 18?
(vi) What is the name given to the energy released, when an atom in its isolated gaseous state accepts an electron to form an anion?
(vii) What is the electronic configuration of the element in the third period which gains one electron to become an anion?
(viii) Fill in the blanks:
The atomic size ______ as we move from left to right across the period, because the ______ increases, but the ______ remains the same.
The electronic configuration of an element is 2, 8, 4. State it:
group and period in the Modern Periodic Table.
Name or state following with reference to the elements of the first three periods of the periodic table.
The number of electron shells in elements of period 1, period 2, and period 3.
Match the option A and B with the statements (i) and (ii):
| A. metal | (i) The metal that forms two types of ion. |
| B. iron | (ii) An element with electronic configuration 2, 8, 8, 3. |
