Explanation :
As we know that Mendeleev arranged the elements in horizontal rows and vertical columns of a table in order of their increasing relative atomic weights.
He placed the elements with similar nature in the same group.
According to the question, the atomic weight of iodine is less than the atomic weight of tellurium. So according to this, iodine should be placed before tellurium in Mendeleev's tables. But Mendeleev placed iodine after tellurium in his original periodic table.
However, iodine has similar chemical properties to chlorine and bromine. So, in order to make iodine queue up with chlorine and bromine in his periodic table, Mendeleev exchanged the positions of iodine and tellurium.
As we know that the positions of iodine and tellurium were reversed in Mendeleev's table because iodine has one naturally occurring isotope that is iodine-127 and tellurium isotopes are tellurium-128 and tellurium-130.
Due to high relative abundance of tellurium isotopes gives tellurium the greater relative atomic mass.
Answer:
28
Explanation:
electron = atomic number - charge(if the charge is positive and addition if the charge is negative)
electron = 30 - 2
electron = 28
Answer:
Instrumental methods
surface analysis
high performance liquid chromatography
atomic spectroscopy
potentiometry
Classical methods
precipitation titration
gravimetric analysis
Explanation:
Instrumental methods of analysis are those analytical methods in which the responsibility of detection has been removed from human beings and placed on automated instruments while classical methods are those analytical methods in which the responsibility of detection remains the responsibility of human beings.
Many instrumental methods such as HPLC rely on computer screens as readout devices.
Answer:
thhe anwer is d
Explanation:
the answer is d just took the quiz got 100 on edge 2022
D.
the total mass of the products will be equal to the original mass of the reactants.
Explanation:
Ca + 2H₂O → Ca(OH)₂ + H₂
From this chemical reaction, one can conclude that when the reaction reaches completion, the total mass of the products will be equal to the original mass of the reactants. This is in compliance with the law of conservation of mass.
- The law of conservation of mass states that matter is the mass of products in a chemical reaction is the same as mass of the reactants.
- This implies that the mass of the products in a given reaction is the same as that of the reactants.
- No mass is lost in the process of a chemical change.
Learn more:
law of conservation of mass brainly.com/question/5896850
law of conservation of matter brainly.com/question/2190120
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