Answer:
A. Rutherford's discovery that atoms contain a nucleus
Explanation:
Explanation:the answer is in this link
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Titration is the slow edition of one solution of unknown concentration to a noun volume up another solution of unknown concentration until the reaction reaches neutralization which is often indicated by a color change
Answer:
Element Helium have<u> 2 energy levels. </u>
Explanation:
<u>HELIUM -</u> With the symbol He and the atomic number 2, helium is a chemical element. It is a colorless , odorless, tasteless, non-toxic, inert, monatomic gas that is the first in the periodic table in the noble gas group. Of all the elements, its boiling point is the lowest.
At about 24 % of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined, it is present. In both the Sun and Jupiter, its abundance is identical to this. This is due to helium-4's very high nuclear binding energy (per nucleon) with respect to the next three elements following helium.
<u>Hence , the answer is 2 energy levels in Helium atom.</u>
B hope this helps, it sounds right
