By considering their position in the Periodic Table,which one of the following elements would you expect to have maximum metallic characteristic?
$Ga$,$Ge$,$As$,$Se$,$Be$

Use Mendeleev's Periodic Table to predict the formulae for the oxides of the following elements: $K, C, Al, Si, Ba$.

In the Modern Periodic Table,calcium (atomic number $20$) is surrounded by elements with atomic numbers $12$,$19$,$21$ and $38$. Which of these have physical and chemical properties resembling calcium?

$Lithium$,$sodium$,and $potassium$ are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?

Name:
$(a)$ three elements that have a single electron in their outermost shells.
$(b)$ two elements that have two electrons in their outermost shells.
$(c)$ three elements with filled outermost shells.

Helium is an unreactive gas and neon is a gas of extremely low reactivity. What,if anything,do their atoms have in common?