Answer:
Various limitations of Mendeleev's periodic table are:-
Position of hydrogen - he couldn't assign a correct position to hydrogen as it showed properties of both alkali and halogens .
Position of isotopes - he considered that the properties of elements are a function of their atomic masses. Hence isotopes of a same element couldn't be placed.
In the d-block , elements with lower atomic number were placed before higher atomic number.
Explanation:
True.
Because some people breathe less pollution and face lower risks of premature death and other serious health
Answer:
Speed of light
Explanation:
The value 3.0 x 10⁸m/s is taken as the speed of light.
It is a constant.
- It implies that light travels a distance of 3 x 10⁸ in just one second.
- This value is for the speed of light in a vacuum when there are not particles obstructing its movement.
- The speed of electromagnetic radiations in free space is also taken as the speed of light.
Ammonium perchlorate appears as a white, crystalline solid or powder. Classified as a division 1.1 explosive if powdered into particles smaller than 15 microns in diameter or if powdered into larger particles but thoroughly dried. Does not readily burn, but will burn if contaminated by combustible material. May explode under prolonged exposure to heat or fire. Used to make rocket propellants, explosives, pyrotechnics, as an etching and engraving agent, and in analytical chemistry.
