Question

Three kids sitting equally apart around a table are sharing jelly beans. One of the kids, however, tends only to take jelly beans and only rarely gives one away. If each jelly bean represents an electron, who ends up being slightly negative? Who ends up being slightly positive? Is the negative kid just as negative as one of the positive kids is positive? Would you describe this as a polar or nonpolar situation? How about if all three kids were equally greedy?

Short answer

The kid who takes more jelly beans ends up slightly negative. The others are slightly positive. It's a polar situation unless all are equally greedy, which would be nonpolar.

Step-by-step solution

Identify the Situation

We have three kids sitting equally apart, and each jelly bean represents an electron. One kid tends to take more jelly beans, indicating they have more electrons compared to the others.

Determine Charge Distribution

The kid who consistently takes jelly beans will accumulate more negatively charged jelly beans (electrons), making them slightly negative. The other kids, on average, will lose some jelly beans, since they end up with fewer jelly beans, making them slightly positive.

Assess Balance of Charges

The negative kid (with excess jelly beans) will not be as negative as the positive kids are positive, because the imbalance is caused by one consistently taking more jelly beans rather than a direct transfer resulting in equal but opposite charges.

Determine Polar or Nonpolar

In this situation, one kid being more negative due to consistently taking jelly beans creates a charge imbalance, which resembles a polar situation due to the uneven distribution of jelly beans (electrons).

Equal Greediness Scenario

If all three kids were equally greedy and took and gave jelly beans at a similar rate, they would each end up with approximately the same number of jelly beans over time, resulting in a nonpolar situation, as the distribution of jelly beans would be more uniform and balanced.

Key concepts

Electron Distribution

In the context of molecules, electron distribution refers to how electrons are arranged around the atoms in a molecule. It's similar to the jelly bean analogy from the exercise, where electrons are like jelly beans that are shared among atoms.
When electrons are not evenly distributed, it can lead to one atom having more electrons while another has fewer.

• Uneven distribution occurs when one atom attracts electrons more strongly.
• Even distribution results in atoms sharing electrons equally.

For molecules, understanding electron distribution is crucial as it affects the overall charge and properties of a molecule.

Charge Imbalance

Charge imbalance occurs when there is an unequal distribution of electric charge within a molecule.
In the jelly bean analogy, this is like one kid ending up with more jelly beans (electrons), making them slightly negative.

• Charge imbalance leads to one side having more negative charge.
• It affects how the molecule interacts with other substances.

This imbalance often results in unique physical and chemical properties for polar molecules, such as solubility in water.

Polar and Nonpolar

Molecules can be categorized as polar or nonpolar based on their charge distribution.
A polar molecule has a significant charge imbalance, resembling the scenario where one kid has more jelly beans than the others.

• Polar molecules have distinct positive and negative regions.
• Water is an example of a polar molecule.

Conversely, nonpolar molecules have a more even distribution of charge, like when all three kids have equal amounts of jelly beans.

Electronegativity

Electronegativity is the ability of an atom to attract electrons towards itself.
In our analogy, it's like how much each kid wants to keep the jelly beans.

• Atoms with high electronegativity attract electrons more strongly.
• Fluorine has the highest electronegativity in the periodic table.

Differences in electronegativity between atoms in a molecule contribute to electron distribution and determine whether a molecule is polar or nonpolar.

Chemical Bonding

Chemical bonding involves the interactions that hold atoms together in a molecule. There are different types of bonds based on electron sharing and distribution.
In covalent bonding, electrons (jelly beans) are shared between atoms.

• Ionic bonds form when electrons are transferred from one atom to another.
• Covalent bonds can result in polar or nonpolar molecules based on electron sharing.

Understanding chemical bonding is fundamental to grasping molecular polarity and the behavior of different substances.