Hello!
Find the Energy of the Photon by Planck's Equation, given:
E (photon energy) =? (in Joule)
h (Planck's constant) = 
f (radiation frequency) = 
Therefore, we have:
I Hope this helps, greetings ... DexteR! =)
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.
Answer:
B. Intermolecular forces are hard to overcome
Explanation:
A high boiling point indicates greater inter molecular forces between the molecules of the substance. Inter molecular forces is the force of attraction between the molecules of the substance, which has to be overcome or broken before the substance boils. Example, when water boils, the water molecule (H₂O) will be broken into hydrogen molecule and oxygen molecule.
Therefore, a high boiling point temperature indicates that intermolecular forces of the substance are hard to overcome.
B. Intermolecular forces are hard to overcome
Answer:
1. The dye that absorbs at 530 nm
Explanation:
With a larger HOMO-LUMO gap, there's also a higher absorption energy, so this means that the dye with the higher absortion energy has the larger HOMO-LUMO gap.
The relationship between energy and wavelenght can be expressed by the formula E = hc/λ, this means that the <em>lower</em> the wavelenght, the <em>higher</em> the energy is. So the dye that absorbs at a lower wavelenght has a larger HOMO-LUMO gap.
