Question

3. The table on the next page is made on the basis of the modern periodic table. Write in it the
electronic configuration of the first 20 elements below the symbol, and write the valency
(as shown in a separate box).
4. What is the periodic trend in the variation of valency while going from left to right within
a period? Explain your answer with reference to period 2 and period 3.
5. What is the periodic trend in the variation of valency while going down a group? Explain
your answer with reference to the group 1, group 2 and group 18.
​

Answer 1

Answer:

5. Valence numbers do not vary as you go down a group, since the periodic table is arranged by atomic number and chemical properties. 》 All members of a group have the same number of valence electrons.