An element $A$ has an atomic number $16$. To which group and period does it belong?

Why does atomic size decrease as we move from left to right along a period in the periodic table?

Write true or false for the statement: In order to fit elements into his table,Newlands adjusted three elements in the same slot,but also put some unlike elements in the same slot.

Which of the following elements would lose an electron easily?

An element which is an essential constituent of all organic compounds belongs to :

$(i)$ State Modern Periodic Law.
$(ii)$ How many :
$(a)$ groups and
$(b)$ periods are present in the modern periodic table?
$(iii)$ State how the problem of placing:
$(a)$ hydrogen,
$(b)$ isotopes of an element has been solved in this periodic table.