Since then, the periodic table has evolved to reflect over 150 years of scientific development and understanding in chemistry and physics. Today, with 118 known elements, it is widely regarded as one ...

So, today we're going to look at the periodic table. That thing that you see ... further confirming that Mendeleev’s understanding was correct. Image caption, The element germanium was ...

So, today we're going to look at the periodic table. That thing that you see ... further confirming that Mendeleev’s understanding was correct. Image caption, The element germanium was ...