Chlorine effective nuclear charge

Was this your answeT Chlorine and oxygen must lie in the same area of the periodic table. Both have strong effective nuclear charges, and both are strong oxidizing agents. 

Of chlorine, oxygen, fluorine, and neon, which has the highest (that is, the most negative) electron affinity Briefly but carefully explain your answer in terms of two of the components of the interconnected network of ideas to make sense of the periodic table. As part of your answer, calculate the effective nuclear charges that operate on electrons being added to fluorine, oxygen, and neon. 

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