, 2s , 2p Which elements among these will belong to the same group of periodic table . Give the general electronic configuration of lanthanides and actinides? . Why halogens act as oxidising agents?
. Mention any two anomalous properties of second period elements. . Explain the pauling method for the determination of ionic radius.
. Explain the periodic trend of ionisation potential. . Explain the diagonal relationship.
. Why the first ionisation enthalpy of sodium is lower than that of magnesium while its second ionisation enthalpy is higher than that of magnesium? . By using paulings method calculate the ionic radii of K + and Cl - ions in the potassium chloride crystal.
Given that d K + -Cl - = . Å . Explain the following, give appropriate reasons. (i) Ionisation potential of N is greater than that of O (ii) First ionisation potential of C-atom is greater than that of B atom, where as the reverse is true is for second ionisation potential.
(iii) The electron affinity values of Be and Mg are almost zero and those of N ( . eV) and P ( . eV) are very low (iv) The formation of F - (g) from F(g) is exothermic while that of O - (g) from O (g) is endothermic. .
What is screening effect? . Briefly give the basis for pauling's scale of electronegativity. .
State the trends in the variation of electronegativity in group and periods. 11th Std Chemistry 11th Std Chemistry - - - - CONCEPT MAP Classification of Elements MODERN PERIODIC TABLE By Mosley-( ) The physical and chemical properties of elements are periodic functions of their atomic number PERIODIC TRENDS IN PROPERTIES OF ELEMENTS Periods and Groups Blocks Groups: Vertical columns contain elements having similar outer electronic con- figurations. ( Groups) Periods: Horizontal rows. Period number corresponds to the highest principal quantum number (n) of the elements.
Periods to contains , , , , , elements respectively. Period contains elements (lanthanides) Period contains elements (actinides) s- block: group- : hydrogen and alkali metals group