Concept:Elements with the same number of valence electrons belong to the same group and show similar chemical properties.Explanation:An element with atomic number 17 is chlorine.Its electronic configuration is 2,8,7.So it has 7 valence electrons.Elements with 7 valence electrons belong to Group 7, the halogens.Among the options, element with atomic number 35 is bromine.Bromine also has the configuration 2,8,18,7, giving it 7 valence electrons.Therefore, chlorine and bromine are in the same group and will resemble each other chemically.Answer:B. 35