Answer:
C) 4.
Explanation:
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In this case, since the electron configuration of nickel at its ground-state, considering 28 as its atomic number and the number of electrons it has in one atom, is:

We can see it has four energy levels, 1, 2, 3 and 4, which are related to the following principal quantum number, that describes the energy of an electron in the atom and its most probable distance with respect to the nucleus.
Therefore, nickel has C) 4 different principal quantum numbers.
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I have written the answer in the comments i hope it will be helpful to you ......
Plants most commonly break large rock into smaller pieces by having the plant root grow into cracks in rocks. The plant root from below the surface grows and that's how they break rocks into pieces.
Answer:
<h2>The answer is 334 g</h2>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
<h3>mass = Density × volume</h3>
From the question
volume of ethanol = 423 cm³
density = 0.789 g/cm³
So we have
mass = 0.789 × 423 = 333.747
We have the final answer as
<h3>334 g</h3>
Hope this helps you