besides gallium, which other elements have since been discovered that were left by Mendeleev in his periodic Table?

What were the criteria used by mendeleev in creating his periodic Table?

An element with atomic number 20 will be placed in which period of the perodic table ?

How were the position of isotopes of various elements decided in the Modern Periodic Table?

Compare and contrast the arrangement of elements in mendeleev's Periodic Table and Modern Periodic Table.

Let, the element with atomic number 117 is discovered today.Which group of the periodic table wil be most suitable for it?Give reason.

Modern periodic tables is based on the atomic number of the elements . The experiment which proved the significance of the atomic number was

The element A has atomic number 15. To which period of the periodic table the element belongs?

In the modern Periodic table, which are the metals among the first ten elements?