Basic Chemistry and Atomic Structure Quiz

Basic Chemistry

• Matter: has mass and occupies space, made of elements and compounds, affected by gravity
• Energy: the ability to do work, potential and kinetic (ex: sound, light, heat), matter has a tendency to move to the lowest energy level
• Element: pure substance, one kind of atom, cannot be broken down
• Compound: 2 or more different elements in a fixed ratio, characteristics may be different than its elements

Atomic Structure

• Atom: smallest unit of an element, retains element's properties, protons, neutrons, and electrons as subatomic particles
• Protons: atomic mass unit (AMU) of 1, positive charge, found in the nucleus
• Neutrons: AMU of 1, no charge, found in the nucleus
• Electrons: negligible AMU, negative charge, found in the electron cloud
• Atomic Number: number of protons in an atom
• Mass Number: number of protons and neutrons in an atom
• Atomic Mass: total AMU of the nucleus
• Isotopes: atoms of the same element with different numbers of neutrons, must have balanced protons and electrons to be neutral, radioactive isotopes are unstable and spontaneously decay
• Electrons: exist at fixed levels of potential energy (electron shells)

Chemical Bonds

• Covalent bonds: strong bonds, characterized by electron pairs shared between atoms
• Single bond: sharing of one pair of electrons
• Double bond: sharing of two pairs of electrons
• Triple bond: sharing of three pairs of electrons
• Polar covalent bond: uneven electron distribution due to differences in electronegativity, unequal sharing
• Nonpolar covalent bond: equal sharing of electrons
• Ionic bond: electron transfer between atoms, forming ions that attract, cation is positive charge, anion is negative charge, forms ionic compounds (salts)
• Hydrogen bond: weaker bond, attraction between the slightly positive hydrogen of one molecule and a slightly negative atom (often oxygen or nitrogen) of another molecule

Water

• Polar molecule: unequal sharing of electrons between hydrogen and oxygen atoms
• Hydrogen bonds: crucial for water's properties, allows surface tension, cohesion (attraction between water molecules), and adhesion (attraction between water and other molecules)
• High specific heat: absorbs significant heat before temperature changes, moderates temperatures
• High heat of vaporization: absorbs a lot of heat to evaporate, cooling effect
• Solvent of life: water dissolves many substances, hydration shell forms around dissolved ions
• Important properties: cohesion, adhesion, surface tension, capillary action, transpiration, moderation of temperature, expansion upon freezing

Chemical Reactions

• Chemical reactions: making or breaking chemical bonds in matter, change composition

Functional Groups

• Hydroxyl (-OH): often found in alcohols, polar, can form hydrogen bonds
• Carbonyl (>C=O): found in sugars, ketones, and aldehydes, polar
• Carboxyl (-COOH): found in organic acids, acidic, can donate H⁺
• Amino (-NH₂): found in amines, basic (accepts H⁺)
• Sulfhydryl (-SH): found in thiols, can form cross-linking bonds in proteins
• Phosphate (-OPO₃²⁻): found in nucleic acids and phospholipids, negatively charged, contribute to molecule's charge
• Methyl (-CH₃): often added to DNA or proteins, affects their function

Organic Compounds

• Carbon: versatile, forms covalent bonds, four bonds
• Isomers: different structures with same molecular formula
• Functional groups: give molecules unique properties
• Monomers/polymers: monomers combine to form polymers by dehydration synthesis
• Hydrolysis: opposite reaction breaks down the polymer using water
• Important macromolecules: carbohydrates, lipids, proteins, nucleic acids

Carbohydrates

• Monosaccharides: simple sugars (glucose, fructose, galactose), building blocks for larger carbs
• Disaccharides: two monosaccharides joined (sucrose, lactose, maltose)
• Polysaccharides: many monosaccharides joined (starch, glycogen, cellulose, chitin), storage and structural functions

Lipids

• Fatty Acids: long hydrocarbon chains, saturated (no double bonds), unsaturated (double bonds)
• Fats and oils: glycerol + fatty acids, saturated fats are solid at room temperature, unsaturated fats are liquid
• Phospholipids: glycerol +2 fatty acids + phosphate, important for cell membranes
• Steroids: 4 fused carbon rings (cholesterol, hormones)
• Hydrophobic: do not mix with water

Proteins

• Amino acids: monomers of proteins (20 different amino acids), determined by sequence
• Peptides/Polypeptides: short/long chains of amino acids, peptide bonds link them
• Levels of protein structure: primary (sequence), secondary (alpha helix, beta sheet), tertiary (3D shape), quaternary (multiple polypeptide chains)
• Denaturation: loss of protein structure, due to pH, temp etc
• Functions: enzymes (catalysts), transport, storage, defense, structure, hormones

Nucleic Acids

• Nucleotide: monomers of nucleic acids (sugar, base, phosphate), joined by phosphodiester bonds
• Types: DNA and RNA
• Base Pairing: A-T/U, C-G
• Structure: DNA double helix, RNA often single-stranded
• Functions: store and transmit genetic information, DNA is the blueprint for proteins
• DNA: deoxyribose sugar, A, T, C, G bases
• RNA: ribose sugar, A, U, C, G bases