Answer:
See explanation
Step-by-step explanation:
We have to remember that a radical species it's a molecule in which we have a homolytic rupture of a bond. In other words, each bond is made from 2 electrons, in the radical formation process, the bond is broken and each atom retains an electron.
This rupture is drawn with the half-headed arrows pointing in opposite directions. Additionally, the radicals are symbolized with a single point.
In this case, the bond C-H has to broken. Therefore an electron remains in the carbon and the other electron goes with the hydrogen and the butyl radical is formed.
See figure 1
I hope it helps!