The ionization energies (kJ/mol) of hydrogen (H), nitrogen (N), sodium (Na), and oxygen (O) are 1,312, 1,402, 1,681, and 1,314, respectively. Which element combination is least likely?
OH–
NO3–
NH4+
NaO–
NaO-
To determine which element combination is least likely, we need to compare the ionization energies of each element.
The ionization energy is the amount of energy required to remove an electron from an atom or ion. Generally, atoms with lower ionization energies are more likely to form positive ions, while atoms with higher ionization energies are more likely to form negative ions.
Let's compare the ionization energies of each element involved in the potential combinations:
- Hydrogen (H): Ionization energy = 1,312 kJ/mol
- Nitrogen (N): Ionization energy = 1,402 kJ/mol
- Sodium (Na): Ionization energy = 1,681 kJ/mol
- Oxygen (O): Ionization energy = 1,314 kJ/mol
Now, let's analyze each combination:
1. OH-: This combination consists of oxygen (O) and hydrogen (H). Since oxygen has a higher ionization energy than hydrogen, it is more likely for oxygen to form a negative ion (O-) than for hydrogen to form a positive ion (H+). Therefore, this combination is likely.
2. NO3-: This combination consists of nitrogen (N) and oxygen (O). Nitrogen has a higher ionization energy than oxygen. Therefore, it is more likely for oxygen to form a negative ion (O-) than for nitrogen to form a positive ion (N+). Therefore, this combination is likely.
3. NH4+: This combination consists of nitrogen (N) and hydrogen (H). Nitrogen has a higher ionization energy than hydrogen. Therefore, it is more likely for hydrogen to form a positive ion (H+) than for nitrogen to form a negative ion (N-). Therefore, this combination is likely.
4. NaO-: This combination consists of sodium (Na) and oxygen (O). Sodium has the highest ionization energy among the elements listed. Therefore, it is less likely for sodium to form a positive ion (Na+) than for oxygen to form a negative ion (O-). Therefore, this combination is least likely.
In conclusion, the element combination that is least likely is NaO-.