Answer:
D because excited electrons fall back.....
1. ₉¹⁹F
2. Mg(OH)₂
3. 2H₂ + O₂ ⇒ 2H₂O
<h3>Further explanation</h3>
1. Fluorine, atomic number : 9 , mass number = 19
Symbol : ₉¹⁹F
protons=electrons=atomic number = 9
neutrons = mass number - atomic mass
Configuration : [He] 2s² 2p⁵
2. Magnesium hydroxide is an ionic compound and is a strong base consisting of 2 ions:
Positive ion: Magnesium: Mg²⁺
negative ion: Hydroxide: OH⁻
The charges of the two are crossed, so that the compound becomes:
Mg(OH)₂
3. Reaction :
H₂ + O₂ --------> H₂O
give coefficient :
aH₂ + bO₂ --------> H₂O
H, left = 2a, right 2⇒2a=2⇒a=1
O, left = 2b, right 1⇒2b=1⇒b=0.5
Reaction becomes :
H₂ + 0.5O₂ --------> H₂O x 2
2H₂ + O₂ --------> 2H₂O
Can you post the question, on here? I cant open the document.
Answer:
quartz
Explanation:
<em>The correct option would be </em><em>quartz.</em>
<u>Allotropy is a phenomenon that describes the natural existence of the same element in different forms with different physical characteristics. Allotropes are therefore different forms of the same element.</u>
Carbon as an element has several allotropes which include diamond, graphite, graphene, amorphous carbon, and fullerenes. Quartz is a crystalline solid that is composed of silicon dioxide and not carbon.
Hence, all the options are carbon allotropes except quartz.
THE RADIUS OF THE TENTH ORBIT IN A HYDROGEN ATOM IS 52.9A°
<h3>How does an electron orbit work? </h3>
The three-dimensional area covering the nucleus of an atom is called electron orbital. Electrons sometimes fill low-energy orbitals which are closer to the nucleus before filling the higher ones. They mostly fill the orbitals as singly as they can and that filling is known as Hund’s rule. In the wave-like property, electrons don’t orbit a nucleus in the way a planet orbits the sun but however, but they exist as standing waves. The lowest energy possible an electron can take is the same as the fundamental frequency of a wave on a string.
the radius of the first orbit =0.0529nm
radius ∝ n²/z
radius of 10th orbit =(0.0529×100)nm=52.9A°
To learn more about Electron orbit,visit:
brainly.com/question/19132667
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