Number of lone pairs on bonded atoms in Carbonate ion is ‘X’. Number of lone pairs on bonded atoms in Sulphite ion is ‘Y’. Difference between X and Y is
Solution
Number of electron pairs ( EP ) = V + M - C + A 2 ; V = Group number of central atom ; M = - H , - X , - OH . . . . monovalent groups attached to central atom ; C = Charge of cation ; A = Charge of anion ; V = 2 , 3 . 4 , 5 , 6 , 7 , 8 respectively for 2 nd , 13 th , 14 th , 15 th , 16 th , 17 th , 18 th group elements ; Number bond pairs , BP ( according to VSEPR theory ) = Number of atoms directly attached to central atom ; = 4 , 4 , 3 , 3 respectively in SO 4 2 - , PO 4 3 - CO 3 2 - , , SO 3 2 - ; * * * According to VSEPR theory , double bond and triple bond are counted as one bond pair only ; If the bonded atom is Oxygen . . . . . Magnitude of Oxidation state of central atom = Total bonds ; Number of atoms directly attached to central atom = sigma bonds ; Total bonds - sigma bonds = pi bonds ; Number lone pairs on central atom ( LP ) = EP - BP ; = 0 , 0 , 0 , 1 respectively in SO 4 2 - , PO 4 3 - CO 3 2 - , , SO 3 2 - ; Note : Each bivalent oxygen atom has ' 2 ' lone pairs on it ; Each monovalent oxygen atom with negative charge has ' 3 ' lone pairs on it SO 4 2 - - ' 4 ' bp + ' 0 ' lp on central atom ; sp 3 - Tetrahedral ; Total 10 lone pairs / ion ; 10 lone pairs on bonded atoms ; . . . . Orientation of electron pairs . . . . Tetrahedral ; PO 4 3 - - ' 4 ' bp + ' 0 ' lp on central atom ; sp 3 - Tetrahedral ; Total 11 lone pairs / ion ; 11 lone pairs on bonded atoms ; . . . . Orientation of electron pairs . . . . Tetrahedral ; CO 3 2 - - ' 3 ' bp + ' 0 ' lp on central atom ; sp 2 - Trigonal planar ; Total 8 lone pairs / ion ; 8 lone pairs on bonded atoms . . . . Orientation of electron pairs . . . . Trigonal planar ; SO 3 2 - - ' 3 ' bp + ' 1 ' lp on central atom ; sp 3 - Pyramidal ; Total 9 lone pairs / ion ; 8 lone pairs on bonded atoms . . . . Orientation of electron pairs . . . . Tetrahedral ; SO 4 2 - ; Magnitude of oxidation number = Total bonds = 6 ; Number of atoms directly attached to central atom = Number of sigma bonds = 4 ; Number of pi bonds = Total bonds - sigma bonds = 2 . . . . . . ' 0 ' pπ - pπ and ' 2 ' dπ - pπ bonds ; PO 4 3 - ; Magnitude of oxidation number = Total bonds = 5 ; Number of atoms directly attached to central atom = Number of sigma bonds = 4 ; Number of pi bonds = Total bonds - sigma bonds = 1 . . . . . . ' 0 ' pπ - pπ and ' 1 ' dπ - pπ bonds ; SO 3 2 - ; Magnitude of oxidation number = Total bonds = 4 ; Number of atoms directly attached to central atom = Number of sigma bonds = 3 ; Number of pi bonds = Total bonds - sigma bonds = 1 . . . . . . ' 0 ' pπ - pπ and ' 1 ' dπ - pπ bonds ; CO 3 2 - ; Magnitude of oxidation number = Total bonds = 4 ; Number of atoms directly attached to central atom = Number of sigma bonds = 3 ; Number of pi bonds = Total bonds - sigma bonds = 1 . . . . . . ' 1 ' pπ - pπ and ' 0 ' dπ - pπ bonds ;