Answer:
Na ·
Explanation:
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In this case, since the Lewis dot structure of any element illustrates the number of valence electrons at the outer shell; we can set up the electron configuration of sodium to obtain:

We can see there is only one valence electron, for that reason the Lewis dot structure is:
Na ·
Whereas the dot represents the valence electron.
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The ion N³⁻ is called the azide ion. In its neutral state, it occurs as the element Nitrogen. The atomic number of Nitrogen is 7. When it turns into an anion (negatively charged ion), it gains 3 more electrons. That's why its net charge becomes -3. It means that the protons is still 7, but the electrons are now 10.
Overall charge = +7 + -10 = -3
Chemical energy is converted to thermal energy.
A hydrogen atom has 0 charge because its two constituents are oppositely charged; and understand p + q as the number located a distance |q| from p, in the positive or negative direction depending on whether q is positive or negative.
Answer:
The moles present in 60 g of calcium are 1.5 moles.