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

Which of the following statements about the Modern Periodic Table is correct?

Which of the following elements would lose an electron easily?

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?

State whether the following statement is true or false: In $1913$,Dmitri Ivanovich Mendeleev showed that the atomic number of an element is a more fundamental property than its atomic mass.

An element $X$ (atomic number $17$) reacts with an element $Y$ (atomic number $20$) to form a divalent halide.
$(a)$ Where in the periodic table are elements $X$ and $Y$ placed?
$(b)$ Classify $X$ and $Y$ as metal$(s)$,non-metal$(s)$,or metalloid$(s)$.