Question

model 2 - electronegativity
read: all atoms want to be stable. for most atoms, stability looks like having a full outer energy level of 8 electrons. some elements are stable on their own. others will form bonds in order to become stable. they do this by gaining, losing, or sharing electrons with the other atoms they bond with. electronegativity is a measure of the ability of an atom in a bond to attract electrons. the greater the difference in electronegativity (δen) between two atoms, the more strongly one of those atoms is attracting the electrons. a δen > 2 results in the formation of an ionic bond, where one atom is giving their electrons and the other is taking. a δen less than 2 but greater than 0.5 results in the formation of a polar covalent bond, where the two atoms share electrons but one has a stronger pull on them. if the difference in electronegativity between two atoms is much smaller (δen < 0.5), then the electrons are being more equally shared, forming a pure covalent bond.

1. the reading refers to elements that are already stable on their own. which elements are those? what makes them stable on their own?
2. define electronegativity.
3. make a prediction about what you think the electronegativity of the category of elements you referenced in number 9 would be. justify your prediction with reasoning.
4. refer to the data table provided for model 2. find the difference in electronegativity between a sodium atom and a chlorine atom. what type of bond would most likely form between sodium and chlorine? explain why this makes sense based on what you know about these elements.
5. refer to the data table provided for model 2. find the difference in electronegativity between a carbon atom and an oxygen atom. what type of bond would most likely form between carbon and oxygen? explain why this makes sense based on what you know about these elements.
6. refer to the data table provided for model 2. find the difference in electronegativity between two hydrogen atoms. what type of bond would most likely form between two hydrogens? explain why this makes sense based on what you know about these elements.

Explanation:

1. Noble gases (e.g., He, Ne, Ar) are stable alone because they have a full outer electron shell (8 electrons, except He with 2).
2. Electronegativity is the ability of an atom in a bond to attract electrons.
3. Noble gases have very low or no electronegativity—they don’t form bonds, so they don’t attract electrons in a bonded state.
4. Na (0.9) and Cl (3.2): ΔEN = 3.2 - 0.9 = 2.3 > 2 → ionic bond. Na loses 1 electron, Cl gains it for stability.
5. C (2.4) and O (3.4): ΔEN = 3.4 - 2.4 = 1.0 (0.5 < 1.0 < 2) → polar covalent bond. They share electrons unevenly.
6. H (2.2) and H: ΔEN = 0 < 0.5 → pure covalent bond. Electrons are shared equally.

Answer:

1. Noble gases (He, Ne, Ar); full outer electron shell.
2. Ability of an atom in a bond to attract electrons.
3. Very low/no electronegativity; they don’t form bonds.
4. ΔEN = 2.3; ionic bond.
5. ΔEN = 1.0; polar covalent bond.
6. ΔEN = 0; pure covalent bond.