Answer:Artificial light from cities has created a permanent "skyglow" at night, obscuring our view of the stars. Here's their map of artificial sky brightness in North America, represented as a ratio of "natural" nighttime sky brightness. In the black areas, the natural night sky is still (mostly) visible.
Explanation:
Less reactive than Group<span> I </span>elements<span>. The reasoning for this is because it is </span>more<span> difficult to lose two electrons compared to losing just </span>one<span> electron. They mostly React with water to form alkaline solutions. ...Now This is because the smaller an atom the closer the outer electrons are to the nucleus.</span>
Answer:
3.6
Explanation:
Step 1: Given data
- Concentration of formic acid: 0.03 M
- Concentration of formate ion: 0.02 M
- Acid dissociation constant (Ka): 1.8 × 10⁻⁴
Step 2: Calculate the pH
We have a buffer system formed by a weak acid (HCOOH) and its conjugate base (HCOO⁻). We can calculate the pH using the <em>Henderson-Hasselbach equation</em>.
![pH = pKa +log\frac{[base]}{[acid]} = -log 1.8 \times 10^{-4} + log \frac{0.02}{0.03} = 3.6](https://tex.z-dn.net/?f=pH%20%3D%20pKa%20%2Blog%5Cfrac%7B%5Bbase%5D%7D%7B%5Bacid%5D%7D%20%3D%20-log%201.8%20%5Ctimes%2010%5E%7B-4%7D%20%2B%20log%20%5Cfrac%7B0.02%7D%7B0.03%7D%20%3D%203.6)
According to Bohr's model of the atom, the higher the orbital in which the electrons are found, the higher their energy or excitation state. Therefore, the electrons with the least amount of energy are those at the lowest orbitals, which are closer to the nucleus.
These orbitals are characterized by 4 quantum numbers, namely the principal quantum number (n), orbital angular momentum quantum number (l), the magnetic quantum number (ml), and the electron spin quantum number (ms). The principal quantum number reflects the distance of the electrons from the nucleus with n=1 as the orbital closest to the nucleus. Thus, according to Bohr's model, electrons in the orbital with n=1 have the lowest energy.
