Variable oxidation numbers are possible for:

If atomic number of an element is 11, the correct name, symbol and valency are :

In which of the following pairs are the element found in the same period of the periodic table?

Which of the following elements is not a Noble gas?

Consider the following statement: "Atomic number of an element is a more fundamental property than its atomic mass." Who among the following scientists has made the above statement?

Which one among the following are the correct symbols for the elements gold, tin and lead, respectively?