1. Write the relation between the subshell electronic configuration of element in each block and the group number.
1.S- block: groupnumber is the number of last s electron
p-block: group number is obtained when 10 is added to the number of last (s+p) electrons
d-block : group number is the sum of the last s electron and the d electron in the
penultimate shell
2. An element exhibits only +2 oxidation state, predict the block and group of this element.
Block s , group 2
3. The electronic configuration of an element is 1S2 2S2 2P6 3S2 3P6 4s2 3d3. Predict the block, period and group of the element.
Block-d , group 5, period 4
4. It is found that a metallic element forms two chloride salts with different colors. What is the assumption about the block of the element ?
d block
5. Why do d block elements show variable oxidation states ?
Due to slight energy difference between s sub shell electrons and d sub shell electrons, during compound formation electrons from s and d may be transferred or shared. Hence the element shows variable valency.