Question

I understand that John Newland’s law of octaves was ridiculed by the scientific community as his table failed to work past calcium. I'm trying to understand how Mendeleev’s table improved on this.

On Mendeleev’s table, do all elements in the same group even past calcium exhibit similar properties? I saw on his table that potassium and copper were in the same group. Calcium and zinc were also in the same group. It seems to me that these elements have different properties.

So why was this accepted? Don't potassium and copper exhibit different properties as well as calcium and zinc? To me, it appears that both Newlands and Mendeleev's tables had elements in the same group with very different properties.

Answer 1

Mendeleev's periodic table was accepted over Newland's Law of Octaves due to its predictive power and the accurate arrangement of elements with similar properties. The table's validation came from the discovery of new elements like gallium and germanium that had properties predicted by Mendeleev.

Step-by-step explanation:

John Newlands's Law of Octaves was an early attempt to classify elements based on their properties and atomic mass. However, it was Dmitri Mendeleev's periodic table that overcame the limitations of Newland's proposal.

Mendeleev arranged the elements into a table based on their atomic masses, similar to Newlands, but he also made adjustments and left gaps for undiscovered elements.

One of Mendeleev's significant revelations was that certain pairs of elements, such as iodine and tellurium, exhibited similar chemical properties despite having different atomic masses. This insight allowed him to arrange the elements more accurately.

Mendeleev's periodic table was widely accepted mostly because of his correct predictions regarding undiscovered elements. When elements like gallium and germanium were discovered with properties that matched his predictions for eka-aluminum and eka-silicon, the scientific community recognized the validity of his periodic table.

Despite initial discrepancies like potassium and copper being in the same group, Mendeleev's table was a working model that anticipated that future discoveries and understanding would resolve these issues.