<h3>Take the weighted average of the individual isotopes.</h3><h3 /><h3>Explanation:</h3><h3>63</h3><h3>C</h3><h3>u</h3><h3> has </h3><h3>69.2</h3><h3>%</h3><h3> abundance.</h3><h3 /><h3>65</h3><h3>C</h3><h3>u</h3><h3> has </h3><h3>30.8</h3><h3>%</h3><h3> abundance.</h3><h3 /><h3>So, the weighted average is </h3><h3>62.93</h3><h3>×</h3><h3>69.2</h3><h3>%</h3><h3> </h3><h3>+</h3><h3> </h3><h3>64.93</h3><h3>×</h3><h3>30.8</h3><h3>%</h3><h3> </h3><h3>=</h3><h3> </h3><h3>63.55</h3><h3> </h3><h3>amu</h3><h3> .</h3><h3 /><h3>If we look at the Periodic Table, copper metal (a mixture of isotopes but </h3><h3>63</h3><h3>C</h3><h3>u</h3><h3> and </h3><h3>65</h3><h3>C</h3><h3>u</h3><h3> predominate) has an approximate atomic mass of </h3><h3>63.55</h3><h3> </h3><h3>g</h3><h3>⋅</h3><h3>m</h3><h3>o</h3><h3>l</h3><h3>−</h3><h3>1</h3><h3> , so we know we are right.</h3>
The oxd state of O is -2
the oxidation state, of O2 is(-2)2
the oxd state of Se will be +4
the oxd state of compound will be zero
<span>The statement is true. Amid the Clinton organization, the administration closed down while Congress and the President consulted over how to diminish the national deficiencies. The spending shortage is the distinction between the cash government takes in, called receipts, and what it spends, called expenses every year.</span>
<span>True , all noble gases have filled outer electron shells, and are nonreactive with other atoms.</span>
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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