Variation of radii within the period and group

Which of the following statements regarding the variation of atomic radii in the periodic table is true?

What is the periodic trend in the variation of valency while going down a group? Explain your answer with reserence to the group 1, group 2 and group 18.

In the modern periodic table, the elements are arranged in the increasing order of their atomic number. This arrangement is based on the modern periodic law, which states that the properties of elements are a periodic function of their atomic numbers. In the modern periodic table, each column is called a group and each row is called a period. Elements within the same group show similarity and gradation in properties. This is due to the same number of electroms in the outermost shell . Based on the above paragraph, answer the following question: What is the trend in the variation of valency while going down a group?

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 3.

Atomic Radius |Variation Of Atomic Radius Along The Period|Variation Of Atomic Radius Along The Group|Radius Of Isoelectronic Species|Ionization Energy|Successive Ionization Energy|Variation Of I.E. In Group|Second I.E. Of Oxygen Is Greater Than Second I.E. Of Nitrogen|Summary