What would be the nature of oxides formed by the elements on the right-hand side of the periodic table?

Nitrogen (atomic number $7$) and phosphorus (atomic number $15$) belong to group $15$ of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?

What is meant by 'group' in the modern periodic table? How do the following change on moving from top to bottom in a group?
$(i)$ Number of valence electrons
$(ii)$ Number of occupied shells
$(iii)$ Size of atoms
$(iv)$ Metallic character of elements
$(v)$ Effective nuclear charge experienced by valence electrons.

What property do all elements in the same column of the Periodic Table as fluorine have in common?

The elements $Be$,$Mg$,and $Ca$,each having two electrons in their outermost shells,are in periods $2$,$3$,and $4$ respectively of the modern periodic table. Answer the following questions,giving justification in each case:
$(i)$ Write the group to which these elements belong.
$(ii)$ Name the least reactive element.
$(iii)$ Name the element having the largest atomic radius.

The atomic number of $Na$ and $Mg$ is $11$ and $12$ respectively and they belong to the same period.
$(a)$ Which one would have smaller atomic size?
$(b)$ Which one would be more electropositive?
$(c)$ To which group would each one belong?