Question

1. describe two ways that an ion forms from an atom.
2. explain why ionic compounds are electrically neutral.

Explanation:

Question 4

1. Ion Formation by Losing Electrons (Cation Formation): Atoms, especially metals, can lose one or more valence electrons. When an atom loses electrons, the number of protons (positive charge) in the nucleus becomes greater than the number of electrons (negative charge) surrounding the nucleus. For example, a sodium atom ($\text{Na}$) has 11 protons and 11 electrons. It tends to lose its single valence electron to achieve a stable electron configuration (like a noble gas). After losing the electron, it has 11 protons and 10 electrons, resulting in a net positive charge of +1, forming the sodium ion ($\text{Na}^+$). This type of ion with a positive charge is called a cation.
2. Ion Formation by Gaining Electrons (Anion Formation): Non - metal atoms often gain one or more electrons. When an atom gains electrons, the number of electrons (negative charge) becomes greater than the number of protons (positive charge) in the nucleus. For instance, a chlorine atom ($\text{Cl}$) has 17 protons and 17 electrons. It has a tendency to gain one electron to achieve a stable electron configuration (similar to a noble gas). After gaining an electron, it has 17 protons and 18 electrons, resulting in a net negative charge of - 1, forming the chloride ion ($\text{Cl}^-$). This type of ion with a negative charge is called an anion.

Ionic compounds are composed of positively charged ions (cations) and negatively charged ions (anions). The formation of an ionic compound occurs through the transfer of electrons from metal atoms (which form cations) to non - metal atoms (which form anions). In the overall ionic compound, the total positive charge contributed by all the cations is equal to the total negative charge contributed by all the anions. For example, in sodium chloride ($\text{NaCl}$), sodium ions ($\text{Na}^+$) have a +1 charge and chloride ions ($\text{Cl}^-$) have a - 1 charge. The number of $\text{Na}^+$ ions is equal to the number of $\text{Cl}^-$ ions in the crystal lattice of $\text{NaCl}$. So, the sum of all positive charges and the sum of all negative charges cancel each other out, resulting in the ionic compound being electrically neutral.

Answer:

1. An atom can form a cation (positive ion) by losing one or more valence electrons (e.g., $\text{Na} \to \text{Na}^+ + e^-$). 2. An atom can form an anion (negative ion) by gaining one or more electrons (e.g., $\text{Cl}+e^- \to \text{Cl}^-$).

Question 5