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:
Answer:
Oxygen and Chlorine
Explanation:
Covalent bonds involve the sharing of electrons between nonmetals.
Answer: sun is directly over the equator
Explanation:
There are only two times of the year when the Earth's axis is tilted neither toward nor away from the sun, resulting in a "nearly" equal amount of daylight and darkness at all latitudes.
Well definitely a scientist
Answer:
Explanation:
Actinoids are the series have 15 element in the periodic table.
Chemistry of actinoids are complicated because of the following reasons.
- Their outer most orbitals are 6d and 7s but most of the electrons resides in 5f orbitals. These orbitals are most exposed to environment and incoming electron picked up by 5f orbital instead of 6d or 7s orbitals.
- They are radioactive elements that couldn't be handle in normal condition to study their properties.
- Their f-orbital can accommodate 14 electrons and they have many variable oxidation state.
- 5d electron donot contribute in the formation of chemical bonds.
- They have a very strong tendency to make complexes
- Most of the actinoides are artificial and are in very minute in amount. they are in very less quantity that is amounts found in nano-grams so are more expensive too and
- As they are radioactive so their half life is very short and in very less time the decay occur so couldn't be study as upon decay their actual properties changed.
Due to all the above reasons it make difficult for a chemist to study about the chemical properties of actinoids.
