What are the strengths and weaknesses of the Mendeleev periodic table?

Advantages:

1. Grouping of elements. He generalized the study of the elements then known to a study of mere 8 groups.

2. Gaps for undiscovered elements. Mendeleev left some gaps in his periodic table. These gaps were left for subsequent inclusion of elements not known at that time. He correctly thought that such elements would be discovered later.

3. Prediction of properties of undiscovered elements. He predicted the properties of then unknown elements om the basis of properties of elements lying adjacent to the vacant slots.

4. Incorrect masses corrected. He was able to correct the values of atomic mass of elements like gold and platinum by placing these elements strictly on the bases of similarities in their properties.

Disadvantages:

1. Anomalous pairs: Argon with atomic mass 39.9 precedes potassium with atomic mass 39.1.

Cobalt with atomic mass 58.9 precedes nickel with atomic mass 58.6.

Tellurium with atomic mass 127.6 precedes iodine with atomic mass 126.9.

2. Position of isotopes: According to Mendeleev's periodic law, isotopes of an element must be given separate places in the periodic table since they have different atomic masses. But they were not assigned separate places.

3.Grouping of chemically dissimilar elements: Elements such as copper and silver bear no resemblance to alkali metals but they have placed in separate groups.

4.Separation of chemically similar elements: Elements that are chemically similar, such as gold and platinum have been placed in separate groups.

5.Electron arrangement: It does not explain the electron arrangement of elements.

6. Position of Hydrogen: It was not given in a fixed position.Explanation:

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.