Which one of the following is the correct order of the valencies of elements Ne, Si, N and Mg?

Which of the following sets of elements has the same valency?

Which of the following elements is not a Noble gas?

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

Which one of the following is the most fundamental characteristic of an element ?

Which one among the following has valency of 3?