The order of reactivity of $K$,$Mg$,$Zn$,and $Au$ with water is

The periodic table consists of $18$ groups. An isotope of copper,on bombardment with protons,undergoes a nuclear reaction yielding element $X$ as shown below. To which group,element $X$ belongs in the periodic table?
${}_{29}^{83}Cu + {}_{1}^{1}H \rightarrow 6{}_{0}^{1}n + {}_{2}^{4}\alpha + 2{}_{1}^{1}H + X$

Which of the following is the correct order of gradually decreasing basic nature of the oxides?

How do you determine the chemical reactivity of a compound? Provide an example.

$Fe x_2$ and $Fe y_3$ are known when $x$ and $y$ are :

$Li$ resembles $Mg$ due to diagonal relationship which is attributed to