Decide whether each pair of elements in the table below will form an ionic compound. If they will, write the empirical formula of the compound formed in the space provided.
| element #1 | element #2 | Forms ionic compound? | empirical formula of ionic compound |
|---|---|---|---|
| potassium | fluorine | | |
| oxygen | cesium | | |
| barium | cesium | yes no | |
| bromine | oxygen | yes no | |
Answer (2)
Potassium and fluorine form an ionic compound with the formula KF.
Oxygen and cesium form an ionic compound with the formula C s 2 O .
Barium and cesium do not form an ionic compound because both are metals.
Bromine and oxygen do not form an ionic compound because both are nonmetals.
The completed table is provided above, summarizing the findings for each element pair.
Explanation
Problem Analysis We need to determine if the given pairs of elements will form ionic compounds and, if so, provide the empirical formula for each compound. Ionic compounds typically form between a metal and a nonmetal due to the transfer of electrons, resulting in positively charged cations and negatively charged anions.
Potassium and Fluorine Potassium (K) and Fluorine (F): Potassium is a metal (Group 1), and fluorine is a nonmetal (Group 17). Potassium tends to lose one electron to form K + , while fluorine tends to gain one electron to form F − . Therefore, they will form an ionic compound. The charges balance in a 1:1 ratio, so the empirical formula is KF.
Oxygen and Cesium Oxygen (O) and Cesium (Cs): Cesium is a metal (Group 1), and oxygen is a nonmetal (Group 16). Cesium tends to lose one electron to form C s + , while oxygen tends to gain two electrons to form O 2 − . To balance the charges, we need two cesium ions for every oxygen ion. Therefore, they will form an ionic compound with the empirical formula C s 2 O .
Barium and Cesium Barium (Ba) and Cesium (Cs): Barium is a metal (Group 2), and cesium is a metal (Group 1). Since both are metals, they will not form an ionic compound. Ionic compounds are typically formed between a metal and a nonmetal.
Bromine and Oxygen Bromine (Br) and Oxygen (O): Bromine is a nonmetal (Group 17), and oxygen is a nonmetal (Group 16). Since both are nonmetals, they will not form an ionic compound. Ionic compounds are typically formed between a metal and a nonmetal.
Final Answer Here's the completed table:
element #1
element #2
Forms ionic compound?
empirical formula of ionic compound
potassium
fluorine
yes
KF
oxygen
cesium
yes
C s 2 O
barium
cesium
no
bromine
oxygen
no
Examples
Ionic compounds are essential in everyday life. For example, sodium chloride (NaCl), or table salt, is an ionic compound that we use to season our food. Understanding how ionic compounds form helps us predict the properties of different materials and design new compounds with specific uses. For instance, lithium fluoride (LiF) is used in ceramics, and magnesium oxide (MgO) is used in insulation. The ability to predict the formation and properties of ionic compounds is crucial in various fields, including chemistry, materials science, and engineering.
Potassium and fluorine form an ionic compound with the formula KF, while oxygen and cesium form Cs₂O. Barium and cesium do not form a compound because both are metals, and bromine and oxygen also do not form a compound as both are nonmetals.
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