The Chemical Foundation of Life

These flashcards cover the chemical foundation of life, including atomic structure, isotopes, types of chemical bonds, the properties of water, the pH scale, and the basics of organic carbon chemistry and functional groups.

Matter

Any substance that occupies space and has mass.

Elements

Unique forms of matter with specific chemical and physical properties that cannot break down into smaller substances by ordinary chemical reactions.

Chemical Symbol

A single capital letter or a combination of two letters used to designate an element.

Atom

The smallest unit of matter that retains all of the element's chemical properties.

Nucleus

The atom's center which contains protons and neutrons.

Proton

A positively charged particle that resides in the atom's nucleus; has a mass of $1\,amu$ and a charge of $+1$ unit.

Neutron

An uncharged particle that resides in an atom's nucleus; has a mass of $1\,amu$.

Electron

A negatively charged subatomic particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a charge of $-1$ unit.

Atomic Mass Unit (amu)

A unit of mass defined as approximately $1.67 \times 10^{-24}\,grams$, also known as one Dalton.

Atomic Number

The characteristic number of protons in an atom, used to distinguish one element from another.

Isotopes

Different forms of the same atom that vary only in the number of neutrons they possess.

Mass Number

The total number of protons and neutrons in an atom.

Periodic Table

An organizational chart of elements developed by Dmitri Mendeleev that indicates each element's atomic number and atomic mass.

Chemical Reactivity

The ability of elements to combine and to chemically bond with each other.

Molecules

Two or more atoms chemically bonded together.

Octet Rule

States that, with the exception of the innermost shell, atoms are more stable energetically when they have eight electrons in their valence shell.

Valence Shell

The outermost electron shell of an atom.

Inert (Noble) Gases

The group 18 elements with filled outer electron shells that are highly stable and non-reactive.

Reactants

The substances used in the beginning of a chemical reaction, typically found on the left side of a chemical equation.

Products

The substances found at the end of a chemical reaction, typically found on the right side of a chemical equation.

Balanced Chemical Equation

A statement of a chemical reaction where each element's number of atoms is the same on both sides of the equation.

Equilibrium

A state of relative balance between reactants and products in a reversible reaction.

Cations

Positive ions that form by losing electrons.

Anions

Negative ions that form by gaining electrons, often designated with an "-ide" ending.

Ionic Bond

A chemical bond that forms between ions with opposite charges, such as sodium ($Na^+$) and chloride ($Cl^-$).

Electrolytes

Ions necessary for nerve impulse conduction, muscle contractions, and water balance, such as sodium, potassium, and calcium.

Covalent Bond

A strong bond formed between atoms of the same or different elements when electrons are shared.

Polar Covalent Bond

A type of covalent bond where atoms unequally share electrons, resulting in slightly positive ($\delta+$) or slightly negative ($\delta-$) charges.

Electronegativity

The ability of some elements to attract electrons, creating partial charges in molecules.

Nonpolar Covalent Bond

A bond formed between two atoms of the same element or different elements that share electrons equally.

Hydrogen Bond

A weak bond between slightly positively charged hydrogen atoms and slightly negatively charged atoms (usually oxygen) in other molecules.

Van der Waals Interactions

Weak attractions between molecules dependent on slight fluctuations of electron densities that require molecules to be very close together.

Hydrophilic

A polar substance that interacts readily with or dissolves in water ("water-loving").

Hydrophobic

Nonpolar compounds, such as oils and fats, that do not interact well with water ("water-fearing").

Solvent

A substance capable of dissolving other polar molecules and ionic compounds.

Sphere of Hydration

A hydration shell formed when water molecules surround a particle to keep it dispersed in solution.

Dissociation

The process where atoms or groups of atoms break off from molecules and form ions, such as when $NaCl$ is added to water.

Cohesion

Attraction between water molecules that keeps them together at the liquid-gas interface; responsible for surface tension.

Surface Tension

The capacity of a substance to withstand rupturing when placed under tension or stress.

Adhesion

The attraction between water molecules and other molecules, such as the walls of a capillary tube.

pH Scale

A scale ranging from $0$ to $14$ that measures the concentration of hydrogen ions ($H^+$) in a solution.

Acid

A substance that increases hydrogen ions' ($H^+$) concentration in a solution, usually by having one of its hydrogen atoms dissociate.

Base

A substance that provides hydroxide ions ($OH^-$) or other negatively charged ions that combine with hydrogen ions, raising the pH.

Macromolecules

Complex molecules such as proteins, nucleic acids, carbohydrates, and lipids that comprise cells and have a carbon backbone.

If xenon has an atomic number of 54 and a mass

number of 108, how many neutrons does it

have?

54

Atoms that vary in the number of neutrons found

in their nuclei are called ________.

Isotopes

When acids are added to a solution, the pH

should ________.

decrease

Which of the following statements is true?

Each carbon atom can bond with as many

as________ other atom(s) or molecule(s).

4

Which type of bond represents a weak chemical

bond?

Which of the following statements is not true?

What makes ionic bonds different from covalent

bonds?

Ionic bonds involve the transfer of electrons between atoms, resulting in charged ions, while covalent bonds involve the sharing of electrons.

Why are hydrogen bonds and van der Waals

interactions necessary for cells?

These weak interactions help stabilize protein structures, facilitate molecular recognition, and contribute to the properties of water essential for life. They are strong enough to keep things in place while still being dynamic

Why can some insects walk on water?

Insects can walk on water due to the surface tension created by water molecules, which allows them to distribute their weight without breaking the surface. They also have hydrophobic coatings on the bottom of their feet.

What property of carbon makes it essential for

organic life?

Carbon's ability to form four stable covalent bonds with a variety of elements allows for the vast diversity of organic molecules, including proteins, nucleic acids, carbohydrates, and lipids.