Which element is placed in the same period as ruthenium but has a higher atomic number than it?

Consider the stable elements through lead (Z = 82). In how many instances are the atomic weights of the elements out of order relative to the atomic numbers of the elements?

What is the significance of the periodic table of elements? Choose the best answer.

The symbol for xenon (Xe) would be a part of the noble gas notation for the element.

What are 1A, 3B, and 7A examples of on the periodic table?

What is the atomic symbol for the element in group 4B (4) and the fourth period?

How is today's periodic table different from the one that Mendeleev published?