Sharer

Most molecules use covalent bonds. Think about water, H₂O. It has two H–O covalent bonds. Methane, CH₄, has four C–H covalent bonds. Ammonia, NH₃, has three N–H covalent bonds. Even the air we breathe has them. Molecular oxygen, O₂, has one O=O double covalent bond. Molecular nitrogen, N₂, has one N≡N triple covalent bond. Most things inside living creatures are like this. Proteins, sugars, fats, DNA. They are mostly held together by covalent bonds.

Covalent bonds come in different strengths. They can be single. That means one shared pair. They can be double. That means two shared pairs. Or they can be triple. That means three shared pairs. The more pairs shared, the stronger the bond. The atoms also get closer together. Triple bonds are the strongest covalent bonds. Nitra's N₂ atmospheric pair is a good example.

Sometimes, atoms share perfectly. This happens when both atoms pull equally. Like H–H in hydrogen gas. Or C–C in a diamond. They share the electrons 50/50. These are equal covalent bonds.

Other times, the sharing isn't quite fair. One atom pulls harder. This happens when one atom is more "electronegative." Take water, O–H. Oxygen pulls the electron pair closer to itself. So, the hydrogen atom ends up a little bit positive. The oxygen atom ends up a little bit negative. This unequal sharing makes water "polar." It means water has a slightly positive end and a slightly negative end.

Beaker introduced Sharer to the class. "This is Sharer!" he boomed. He held up the glowing shape. "Sharer is the covalent bond. See? No face. Sharer is not a being. Sharer is a force. It's the force between atoms. Atoms that share electrons. Look at the overlapping circles. Two atoms. One shared pair. That's the whole figure. The force is the figure."

In ChemQuest classrooms, Sharer often appeared. It would pop up next to cast members. They would be forming covalent bonds. Most often, Hydra and Oxy would stand together. Sharer would appear between them. This showed how water, H₂O, was made. Or Carbo and Hydra would join up. Sharer would show the methane, CH₄, bond. Sometimes Carbo would link with another Carbo. Sharer would show a carbon chain.

Beaker always made sure to explain the difference. "Tugger is full transfer," he'd say. "That's an ionic bond. Sharer is a shared pair. That's a covalent bond. Both are bonds. But they are different kinds of forces."

Sharer's lessons were important. Beaker taught them for Sharer. A covalent bond means shared electrons. They sit in overlapping spaces. It's not about taking. It's about sharing. Bonds can be single, double, or triple. One, two, or three shared pairs. More pairs mean a stronger bond. The atoms are also closer. Sharing can be equal or unequal. Equal sharing is like H–H or C–C. The atoms pull the same. Unequal sharing is like O–H or N–H. One atom pulls harder. This makes polar covalent bonds. Polar covalent bonds are still sharing. But the sharing is uneven. Polar bonds make polar molecules. Water is a polar molecule. It acts differently from nonpolar molecules. Methane is nonpolar. Most living things are made of covalent bonds. Proteins, fats, sugars, DNA. They all use covalent bonds. Some have polar covalent bonds too. These help them do their jobs. Covalent compounds are usually molecules. They are separate little groups. They don't form big lattices. They often have lower melting points. They usually don't conduct electricity. * Remember the big rule: shared, not transferred. For covalent bonds, both atoms hold the electrons. For ionic bonds (Tugger's job), one atom takes them all. This difference is key.

Beaker often pointed to Sharer. "Sharer has no face," he said. "That's the lesson. The shared bond is a force. It's not a person."