chapter 2 study guide

Atomic Number

Number of protons in an atom.

Atomic Mass

Total number of protons and neutrons.

Isotope

Same element, different number of neutrons.

Arrangement of Electrons

How electrons are organized around the nucleus.

Ionic Bond

Bond formed when electrons are transferred between atoms.

Covalent Bond

Bond formed when atoms share electrons.

Hydrogen Bond

Weak attraction between hydrogen and another molecule.

Importance of Water

Needed for life, transports substances, and regulates temperature.

Properties of Water

Sticky, dissolves many substances, resists temperature change.

Structure of Water

One oxygen and two hydrogen atoms (H₂O).

Reactant

Substance that starts a chemical reaction.

Product

Substance made by a chemical reaction.

Solvent

Substance that does the dissolving.

Solute

Substance being dissolved.

Adhesion

Water sticking to other surfaces.

Cohesion

Water sticking to itself.

pH Scale

Measures how acidic or basic something is (0–14).

Acid

Releases H⁺ ions into solution; pH below 7.

Base

Releases OH⁻ ions into solution; pH above 7.

Buffer

Helps keep pH stable.

Organic Molecule

Contains both carbon (C) and hydrogen (H).

Inorganic Molecule

Does not contain both carbon and hydrogen.

Carbohydrates

Quick energy.

Lipids

Long-term energy storage and insulation

Proteins

Build and repair tissues; enzymes.

Nucleic Acids

tore genetic information (DNA and RNA).

Monomer

Small building block molecule.

Polymer

Large molecule made of many monomers.

Anabolic Reaction

Builds larger molecules from smaller ones.

Dehydration Synthesis

Joins molecules together by removing water.

Catabolic Reaction

Breaks large molecules into smaller ones.

Hydrolysis

Breaks molecules apart by adding water.

Unsaturated Fat

Usually liquid at room temperature; healthier fat.

Saturated Fat

Usually solid at room temperature; less healthy fat.

HDL

“Good” cholesterol; removes excess cholesterol from blood.

LDL

“Bad” cholesterol; can clog arteries.