What basic properties of Mendeleev's periodic table are similar to the current one?

In Mendeleev's periodic table there were gaps for undiscovered elements. Modern periodic table maintains uniformity. In Mendeleev's periodic table noble gases were not placed (as they are not discovered at that time). In Modern periodic table noble gases in a seperate group named as group-18.

Explanation:

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.