Which of the following pairs of elements are likely to form an ionic compound?
lithium and chlorine
sodium and potassium
phosphorus and chlorine
sodium and nitrogen
argon and potassium
a is the only answer. How do you know? Look up the electronegativities and subtract them. The difference in EN must be about 1.8 or so to be more ionic than covalent.
To determine which of the following pairs of elements are likely to form an ionic compound, we need to look at the electronegativity difference between the elements.
Ionic compounds are formed when there is a significant difference in electronegativity between the elements. Electronegativity is the tendency of an atom to attract electrons towards itself in a chemical bond.
One way to compare electronegativity is to use the Pauling electronegativity scale. The higher the electronegativity difference, the more likely it is for the elements to form an ionic compound.
In the given pairs of elements:
1. Lithium (Li) and Chlorine (Cl): The electronegativity difference between Li and Cl is 3.0 - 0.98 = 2.02. This is a high electronegativity difference, indicating that lithium and chlorine are likely to form an ionic compound.
2. Sodium (Na) and Potassium (K): The electronegativity difference between Na and K is 0.93 - 0.82 = 0.11. This is a very small electronegativity difference, suggesting that sodium and potassium are not likely to form an ionic compound.
3. Phosphorus (P) and Chlorine (Cl): The electronegativity difference between P and Cl is 3.0 - 2.83 = 0.17. This is a relatively small electronegativity difference, indicating that phosphorus and chlorine are not likely to form an ionic compound.
4. Sodium (Na) and Nitrogen (N): The electronegativity difference between Na and N is 0.93 - 3.04 = -2.11. This negative value indicates a large electronegativity difference favoring the formation of an ionic compound between sodium and nitrogen.
5. Argon (Ar) and Potassium (K): Both Argon and Potassium are not likely to form an ionic compound because they are both nonmetals and have similar electronegativities.
Therefore, the pair of elements likely to form an ionic compound are:
- Lithium (Li) and Chlorine (Cl)
- Sodium (Na) and Nitrogen (N)
To determine which pairs of elements are likely to form an ionic compound, we need to consider the electronegativity difference between the elements.
Ionic compounds are formed when there is a large difference in electronegativity between the elements, with one element having a significantly higher electronegativity than the other.
Let's calculate the electronegativity differences for each pair:
1. Lithium and Chlorine:
The electronegativity value for lithium is 0.98, and for chlorine, it is 3.16.
Electronegativity difference = 3.16 - 0.98 = 2.18
2. Sodium and Potassium:
Both sodium and potassium have similar electronegativity values, which are 0.93 and 0.82, respectively. The electronegativity difference is very small.
3. Phosphorus and Chlorine:
The electronegativity value for phosphorus is 2.19, and for chlorine, it is 3.16.
Electronegativity difference = 3.16 - 2.19 = 0.97
4. Sodium and Nitrogen:
The electronegativity value for sodium is 0.93, and for nitrogen, it is 3.04.
Electronegativity difference = 3.04 - 0.93 = 2.11
5. Argon and Potassium:
Argon is a noble gas and is chemically stable, so it does not typically form ions. Potassium has an electronegativity of 0.82.
Based on the electronegativity differences calculated, the pair likely to form an ionic compound is:
- Lithium and Chlorine (with an electronegativity difference of 2.18).
Therefore, the pair of elements likely to form an ionic compound is lithium and chlorine.