Question

# In group 17 how many valence electrons does Iodine have? How many valence electrons does chlorine have?

-The atomic number of Iodine is 53 so, its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{10}}4{{p}^{6}}5{{s}^{2}}4{{d}^{10}}5{{p}^{5}}$. The last shell is 5 and the electrons in the last shell is 7 (2+5).
The atomic number of chlorine is 17 so, its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{5}}$. The last shell is 3 and the electrons in the last shell is 7 (2+5).