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प्रश्न
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
उत्तर
(b) B, C, D:
B, C and D, with atomic numbers 3,7 and 10 respectively, belong to the same period of the periodic table. This is because the elements B, C and D have the same valence shell (L shell).
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संबंधित प्रश्न
Two elements ‘P’ and ‘Q’ belong to the same period of the modern periodic table and are in Group 1 and Group 2, respectively. Compare their following characteristics in tabular form:-
(a) The number of electrons in their atoms
(b) The sizes of their atoms
(c) Their metallic character
(d) Their tendencies to lose electrons
(e) The formula of their oxides
(f) The formula of their chlorides
What happens to the metallic character of the elements as we go down in a group of the periodic table?
Why do elements in the same group show similar properties but the elements in different groups show different properties?
State the valency of the elements of periods 3 and write the formula of their oxides.
Name the element which has the electronic configuration 2, 8, 3?
Four elements P, Q, R and S belong to the third period of the Modern Periodic Table and have respectively 1, 3, 5 and 7 electrons in their outermost shells. Write the electronic configurations of Q and R and determine their valences. Write the molecular formula of the compound formed when P and S combine.
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.
What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 3?
Name or state following with reference to the element of the first three periods of the periodic table.
The non-metallic element present in period 3 other than sulphur and chlorine.
Which of the following would weigh the least?
(Atomic masses C = 12, 0 = 16, Na = 23)
