Answer:
107.87 grams
Explanation:
One mole of silver weighs 107.87 grams
.
Answer:
If it is a solid, liquid or gas
Explanation:
The correct answer is:
They have a low boiling point because of weak intermolecular forces.
Answer: Wavelength associated with the fifth line is 397 nm
Explanation:
= Wavelength of radiation
E= energy
For fifth line in the H atom spectrum in the balmer series will be from n= 2 to n=7.
Using Rydberg's Equation:
Where,
= Wavelength of radiation
= Rydberg's Constant =
= Higher energy level = 7
= Lower energy level = 2 (Balmer series)
Putting the values, in above equation, we get
Thus wavelength λ associated with the fifth line is 397 nm
Answer:
- <em>He realized that some elements had not been discovered.</em>
Explanation:
Some scientists that tried to arrange the list of elements known before Mendeleev include Antoine Lavoisier, Johann Döbereiner, Alexandre Béguyer de Chancourtois, John Newlands, and Julius Lothar Meyer.
<em>Dimitri Mendeleev</em> was so succesful that he is recognized as the most important in such work.
Mendeleev by writing the properties of the elements on cards elaborated by him, and "playing" trying to order them, realized that, some properties regularly (periodically) repeated.
The elements were sorted in increasing atomic weight (which is not the actual order in the periodic table), but when an element did not meet the pattern discovered, he moved it to a position were its properties fitted.
The amazing creativity of Mendeleev led him to leave blanks for what he thought were places that should be occupied by elements yet undiscovered. More amazing is that he was able to predict the properties of some of those elements.
When years after some of the elements were discovered, the genius of Mendeleev was proven because the "new" elements had the properties predicted by him.
