Which of the following elements would lose an electron most easily?

Which of the following are the characteristics of isotopes of an element?

$\left(\mathrm{i}\right)$ Isotopes of an element have same atomic masses.

$\left(\mathrm{ii}\right)$ Isotopes of an element have same atomic number.

$\left(\mathrm{iii}\right)$ Isotopes of an element show same physical properties.

$\left(\mathrm{iv}\right)$ Isotopes of an element show same Chemical properties.

Three elements $\mathrm{B}, \mathrm{Si}$and$\mathrm{Ge}$ are

Three elements $\mathrm{B}, \mathrm{Si}$ and $\mathrm{Ge}$ are: