Question 1 Define atomic number? Question 2 Define mass number? Question 3 Define valency? Question 4 What are valence electrons? Question 5 What are noble gases? Question 6 An element has atomic number 12.How many electrons are present in K,L,M shell? Question 7 Write the distribution of electrons in an atom of element whose atomic number is 18? Atomic … [Read more...] about Valency