Explanation:
1. Electrons surround the nucleus in defined regions called orbits.
2. The shells further away from the nucleus are larger and can hold more electrons.
3. The shells closer to the nucleus are smaller and can hold less electrons.
4. The closest shell (closest to the nucleus) can hold a maximum of two electrons.
5. Once the first shell is full, the second shell begins to fill. It can hold a maximum of eight electrons.
6. Once the second shell is full, the third shell begins to fill.
7. Once the third shell contains Eighteen electrons, the fourth shell begins to fill.
8. The arrangement of electrons in shells around the nucleus is referred to as an atom's electronic configuration.
N₂O₄ (g) ⇌ 2 NO₂ (g)
Kc = [ NO₂ ]² / [ N₂O₄ ]
4.2 = [ 0.785 ] [ N₂O₄ ]
[ N₂O₄ ] = 4.2 / 0.785
[N₂O₄ ] = 5.350 M
hope this helps!
Each natural element has a characteristic light spectrum that helps identify it in samples of unknown substances. Spectroscopy is the practice of examining spectra and comparing them to those of known elements. Using spectroscopy methods, scientists can identify pure substances or compounds and the elements in them.
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PLEASE MARK BRAINLIEST!</u></h2>
It is believed that, 66 million years ago, the first human lived. This is according to fossil. It is thought that, after the Cretaceous–Paleogene extinction [the extinction of dinosaurs and 3/4 of plant and animal life], the first humans appeared.
I hope this helps!