Mendeleev´s Periodic Table Flashcards

All 5 cards in this deck

How did Mendeleev arrange the elements in his periodic table?

In order of increasing relative atomic mass, grouping elements with similar properties (of the elements and their compounds) in the same column.

Why did Mendeleev leave gaps in his periodic table?

For elements that had not yet been discovered, so that elements with similar properties stayed in the same group.

How did Mendeleev predict the properties of undiscovered elements?

He used the properties of the neighbouring elements (and their compounds) around each gap.

Why did ordering by relative atomic mass sometimes put elements in the wrong place, so Mendeleev had to swap some pairs?

Because of the relative abundance of isotopes of some pairs of elements, the heavier element can have the smaller atomic number.

What evidence supported Mendeleev's periodic table after he published it?

Elements he had left gaps for were later discovered, and their properties closely matched his predictions.

e.g. gallium, which he had called eka-aluminium