Problem 95 - Chemistry: An Atoms-Focused Approach

Question

How can we use electronegativity to predict whether a bond between two atoms is likely to be covalent or ionic?

Step-by-Step Solution

Answer

Answer: To use electronegativity to predict the bond type between two atoms, follow these steps: 1. Define electronegativity as a measure of an atom's tendency to attract a bonding pair of electrons. 2. Know the electronegativity difference thresholds, which are less than 1.7 for covalent bonds and equal to or greater than 1.7 for ionic bonds. 3. Identify the elements involved in the bond and find their electronegativity values from a periodic table or a table of electronegativity values. 4. Calculate the electronegativity difference by subtracting the smaller value from the larger one. 5. Determine the bond type based on the electronegativity difference, using the thresholds mentioned above.

Step 1: Define Electronegativity

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The electronegativity values of elements in the periodic table were provided by Linus Pauling, and these values range from 0.7 (francium) to 4.0 (fluorine). A higher value of electronegativity indicates a stronger attraction for electrons.

Step 2: Know the Electronegativity Difference Thresholds

To predict if a bond is covalent or ionic, we can use the difference in electronegativity values between the two atoms involved in the bond. - If the electronegativity difference is less than 1.7, the bond is considered covalent. - If the electronegativity difference is equal to or greater than 1.7, the bond is considered ionic. These thresholds are approximate and may vary slightly in different textbooks.

Step 3: Identify the Elements and Find Their Electronegativity Values

To determine the bond type between two atoms, first identify the elements and find their respective electronegativity values. This information can be obtained from a periodic table which displays electronegativity values or by referring to a table of electronegativity values.

Step 4: Calculate the Electronegativity Difference

Subtract the smaller electronegativity value from the larger one to calculate the electronegativity difference between the two elements in the bond. Electronegativity difference = | Electronegativity of atom 1 - Electronegativity of atom 2 |

Step 5: Predict the Bond Type

Based on the electronegativity difference, determine if the bond is covalent or ionic. Remember to use the thresholds mentioned in Step 2: - If the electronegativity difference is less than 1.7, the bond is covalent. - If the electronegativity difference is equal to or greater than 1.7, the bond is ionic.