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To determine the fraction of the hydrogen atom's mass that is in the nucleus, we have to keep in mind that
a Hydrogen atom has 1 proton and 1 electron.
Protons are in the nucleus while electrons are in electron shells surrounding the nucleus.
The mass of the nucleus will be equal to the mass of 1 proton and we can express the fraction as follows:
So, the fraction of the hydrogen atom's mass that is in the nucleus is
0,9995. That means that almost all the mass of this atom is at the nucleus.
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Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
My Apoligies for not being sooner.
Answer: The closer the particles get or the further apart they get, the greater the sound's amplitude. Sound amplitude causes a sound's loudness and intensity. The bigger the amplitude is, the louder and more intense the sound. - (This is copied)
General Answer : Its a change in sound, bassically the bigger the waves are, the louder the sound is.
Your body uses water in all its cells, organs, and tissues to help regulate its temperature and maintain other bodily functions. Because your body loses water through breathing, sweating, and digestion, it's important to re-hydrate by drinking fluids and eating foods that contain water.
To determine the element that has an electron configuration of <span>[Xe] 6s2 4f14 5d10 6p2, we must know the atomic number of Xe. From the periodic table, Xe has an atomic number of 54. We add the proceeding electrons, which is now a total of 82. The element with this atomic number is lead, Pb.</span>