In the reaction of lithium, \(\mathrm{Li}\), with nitrogen, \(\mathrm{N}_{2}\) three lithium atoms react with one nitrogen atom to give the compound \(\mathrm{Li}_{3} \mathrm{~N}\). Atoms of one of these elements lose one electron; atoms of the other element gain three electrons. (a) Which element gains the three electrons? Explain your choice. (b) Does the element that gained three electrons become a cation or an anion? (c) Give the full atomic symbol for the ion of part (b), assuming it has seven neutrons in its nucleus.

Understanding the flow of electrons is essential to grasp the workings of a chemical reaction. In the reaction between lithium (Li) and nitrogen (N₂), an electron transfer process occurs, which is fundamental to making chemical bonds.

Atoms seek stability through the attainment of a full outer electron shell, resembling the noble gases' configuration. Elements on the left side of the periodic table, particularly those in Group 1 such as lithium, tend to lose electrons and form positive ions, termed cations. Conversely, elements towards the right, like nitrogen from Group 15, are more inclined to gain electrons, resulting in negatively charged ions, known as anions.

This electron transfer can be visualized as a transaction—each lithium atom donates one electron to the 'electron bank,' and nitrogen withdraws three to become stable. Thus, creating a balance in charge as lithium becomes Li⁺ and nitrogen Ng^3-. This exchange of electrons is the linchpin of the lithium and nitrogen reaction.

The product of electron transfer is often ionic compounds, which are substances composed of charged ions held together by electrostatic forces. The reaction between lithium and nitrogen resulting in lithium nitride (Li₃N) involves the formation of such a compound.

The ions in lithium nitride are formed through the electron transfer described earlier. Lithium, after losing an electron, and nitrogen, after gaining three electrons, interact through their opposite charges, leading to the creation of an ionic bond. Ionic compounds are typically solid at room temperature and have high melting and boiling points due to the strong attraction between the oppositely charged ions.

Lithium nitride is a saltlike compound because it is composed of lithium cations (Li⁺) and nitrogen anions (N^3-), that are held tightly in a crystal lattice, showcasing the characteristic properties of ionic compounds such as brittleness, electrical conductivity when molten, and often high solubility in water.

Atomic symbol notation is a shorthand used by chemists to convey information about the structure of atoms and ions. The atomic symbol includes the element's symbol from the periodic table, the atomic number (indicating the number of protons), and the mass number (sum of protons and neutrons). Ions also include a charge notation.

For example, the full atomic symbol for the nitrogen anion created from the lithium and nitrogen reaction is ₇¹⁴_3-. This indicates that the nitrogen ion has seven protons (atomic number is 7), a total of 14 nucleons (a mass number of 14 indicating 7 neutrons), and a 3- charge reflecting the addition of three electrons. The atomic symbol notation is invaluable in quickly understanding an ion's or atom's characteristics without detailing its entire structure.

The periodic table is an organized chart of elements structured by increasing atomic number and grouped according to shared characteristics and properties. Grouping the elements facilitates the understanding of their behavior and how they'll interact in a chemical reaction.

Lithium resides in Group 1 (also known as alkali metals), which contains elements known for being highly reactive and having one electron in their outermost shell, predisposing them to lose that electron easily. Nitrogen belongs in Group 15 (sometimes called pnictogens), which have five outer electrons and tend to gain electrons to complete their valence shell.

These group characteristics explain why lithium loses an electron in our chemical equation and why nitrogen gains three – it's predictable behavior based on their group properties. Comprehending the periodic table groups allows one to anticipate the types of ions an element will form and the nature of their chemical reactions.