4
There are 16 electrons in this ion. 7 from nitrogen, 8 from oxygen and the other one is from the ionic charge.
Nitrogen can gain three electrons to form an ion with a charge of -3. This would give nitrogen a stable octet of electrons in its outer shell, following the octet rule.
A nitrogen ion can have different charges, but for example, a nitrogen ion with a +3 charge would have lost 3 electrons from the neutral nitrogen atom (which has 7 electrons). Therefore, the nitrogen ion with a +3 charge would have 4 electrons.
Seven from the nitrogen atom, eight from each of the three oxygen atoms, and one more from a metal or group that forms a nitrate salt, for a total of 32.
Nitrogen is a unique element. It can loose one, two, three, four, or even five electrons. It can also gain one, two, or three electrons. These are not the only possibilities, however they are the most common.
There is one lone pair of electrons on the nitrogen atom.
There is one lone pair of electrons on the nitrogen atom.
The nitrite ion (NO2^−) has one lone pair of electrons. In its Lewis structure, the nitrogen atom is bonded to two oxygen atoms, with one double bond and one single bond. The single-bonded oxygen atom carries a negative charge and has three lone pairs, while the nitrogen itself has one lone pair. Thus, the total number of lone pairs in the nitrite ion is four: three on one oxygen and one on nitrogen.
All of the electrons are paired. If you are asking how many lone pairs, there are 4.
A potassium ion (K+) has 18 electrons. Potassium has 19 electrons in its neutral state, but when it loses one electron to become an ion, it has 18 electrons.
One lithium ion can bond with one nitrogen ion because lithium has a +1 charge and nitrogen has a -3 charge, resulting in a stable ionic bond between one lithium ion and one nitrogen ion via the transfer of one electron from lithium to nitrogen to achieve a full valence shell.
The NO- ion would have 11 valence electrons. This is because nitrogen typically has 5 valence electrons and oxygen typically has 6 valence electrons in their neutral states, so NO- would have 5 + 6 = 11 valence electrons.