Final answer:
Fluorine, being the smallest halogen, is represented by a small sphere, bromine by a medium sphere due to its larger atomic size, and the bromide ion, Br-, by a big sphere since anions have larger radii than their neutral atoms. Therefore, the correct answer is option B.
Step-by-step explanation:
The spheres that the charges F, Br, and Br- would represent are based on their relative atomic and ionic sizes. To determine which sphere represents which chemical species, we refer to periodic trends and ionic radii.
The atomic radius tends to increase down a group and decreases across a period. For the halogens such as fluorine (F) and bromine (Br), bromine being lower in the periodic table will have a larger atomic radius. Therefore, in their atomic state, bromine's atomic radius is larger than that of fluorine. When it comes to ionic radii, the radius of an anion (negatively charged ion) will be larger than the radius of its neutral atom due to the increased repulsion between electrons when an extra electron is added, in this case Br- having a larger radius than neutral Br.
Thus, given these periodic trends, fluorine being the smallest halogen will be represented by the small sphere, bromine will be the medium sphere, and the bromide ion (Br-) which is larger than its neutral atom, will be the big sphere.
Therefore, the correct answer is: F: Small sphere, Br: Medium one, Br-: Big one, which corresponds to option B.