Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice ?

Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.

Why do you think the noble gases are placed in a separate group ?

Which element has

$(a)$ two shells, both of which are completely filled with electrons?

$(b)$ the electronic configuration $2,\,8,\,2 ?$

The position of three elements $A$, $B$ and $C$ in the Periodic Table are shown below

$(a)$ Will $C$ be larger or smaller in size than $B$ ?

$(b) $ Which type of ion, cation or anion, will be formed by element $A$ ?