(c) When a radioactive isotope decays it can produce beta particles.
What is a beta particle?

Explanation:

Beta particles are of two types - negative beta particles or negatrons and positive beta particles or positrons which are both formed from some nuclear processes within the nucleus.

A negatron is like an orbital electron but it has more energy compared to an orbital electron.

A positron is essentially the same as a negatron except in the charge it carries. A positron carries positive charges.

A beta particle is very light and has much range through matter.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.