Mention any two trends exhibited by elements when we go from left to right across the period of the periodic table.

$(a)$ Electropositive nature of the element$(s)$ increases down the group and decreases across the period.
$(b)$ Electronegativity of the element decreases down the group and increases across the period.
$(c)$ Atomic size increases down the group and decreases across a period (left to right).
$(d)$ Metallic character increases down the group and decreases across a period.
On the basis of the above trends of the Periodic Table,answer the following about the elements with atomic numbers $3$ to $9$:
$(a)$ Name the most electropositive element among them.
$(b)$ Name the most electronegative element.
$(c)$ Name the element with the smallest atomic size.
$(d)$ Name the element which is a metalloid.
$(e)$ Name the element which shows maximum valency.

Which of the following elements will form an acidic oxide?

Two elements $M$ and $N$ belong to group $I$ and $II$ respectively and are in the same period of the periodic table. How do the following properties of $M$ and $N$ vary:
$(a)$ sizes of their atoms?
$(b)$ their metallic characters?
$(c)$ their valencies in forming oxides?
$(d)$ formulae of their chlorides?

Write the formula of the product formed when the element $A$ (atomic number $19$) combines with the element $B$ (atomic number $17$). Draw its electronic dot structure. What is the nature of the bond formed?

Predict the maximum number of valence electrons possible for atoms in the first period of the periodic table.