Element X has 17 protons, 17 electrons, atomic number 17, representing chlorine with electronic configuration 2, 8, 7 and seven valence electrons. Adding two neutrons raises mass number to 37, forming its isotope.
Aman was discussing the structure of atom with his classmates. During the discussion, he learnt that an element X has a mass number of 35 and contains 18 neutrons. Based on this information, answer the following questions: (i) How many electrons and protons does element X have? (ii) What is its atomic number? (iii) Identify the element X. (iv) Write its electronic configuration. (v) How many valence electrons does it have? (vi) What will be the mass number if two neutrons are added to its nucleus? (vii) What will be the relation of X with the new atom?
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Subtracting 18 neutrons from mass number 35 gives 17 protons and 17 electrons. Its atomic number is 17, identifying it as chlorine Cl. The electronic configuration is 2, 8, 7, having seven valence electrons. Adding two neutrons increases its mass number from 35 to 37. Since both atoms have identical atomic numbers but different mass numbers, the new atom is an isotope of chlorine.
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