Atoms & Chemical Bonds. Carbon & Macromolecules

Questions:

1. Explain how the atomic number and mass number of an atom can be used to determine the number of electrons and of neutrons respectively.

In an atom the atomic number represents the number of protons in an atom, which also happens to amounts to the same number of electrons. The mass number is the total number of protons and neutrons in the atom, so if you take the number of protons and subtract it by the mass number you get your number neutrons.

2. Explain how potential energy relates to the position of electrons within the atom.

Depending on how much electro negativity an electron has

3. Distinguish between orbital and electron shell.

Every atom basically has an infinite number of shells; each shell (energy level) has a number of stable paths (orbits) that electrons can move in. Orbital are a region of space around the atom's nucleus where electrons are likely to be found. Keep in mind that orbitals can only carry up to two electrons at most.

4. Distinguish among ionic, non-polar covalent, polar covalent bond, and hydrogen bond.

Ionic bonds are a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. For example Na+ Cl-

Non-polar covalent bonds are a bond between two nonmetal atoms that have the same electronegativity and have an equal share of the bonding electron pair. Ex: H-H

Polar covalent bonds are two nonmetal atoms that have different electronegativity and have an unequal share in the bonding of the electron pair. Ex: H-Cl

Hydrogen bonds are arrangements that keep molecules and compounds together using hydrogen. Ex: H2O

5. Define salt and molecule.

Salt is known as Sodium chloride (NaCl), a white crystal-like substance that is an ionic compound formed by an acid with a base and consists of a metal cation bonded to a non-metal anion.

Molecule is when two or more atoms join together chemically. These molecules are held by covalent bonds

6. Explain the chemical-biological relevance of polar molecules.

Polar molecules are highly reactive because they present a delta negative area (δ-), which is caused by a high density of electrons. Delta positive (δ+) area caused by a low density of electrons. Opposites attract, so negative charged atoms attract possitive charged atoms and vice versa.

7. Explain why strong covalent bonds and weak bonds are both essential in living organisms.

Strong covalent bonds are ideal for supporting a molecular structure. Weak bonds allow for quick dissociation of compounds thus causing the release of the atoms involved, which can be used for a variety of metabolic pathways. Weak bond on the other hand are crucial to help shape macromolecules.

8. Explain how carbon's electron configuration and valence result in its ability to form large and complex organic molecules.

Carbon is a nonpolar tetrahedral with four electrons in it valence shell. This means carbon can establish four more covalent bonds. These tetra valences make large complex molecules possible.

9. Define structural isomers, geometric isomers, and enantiomers.

Structural isomers have the same molecular formula but different structural formulas

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