The Chemical Level of Organization

These flashcards cover essential vocabulary related to the chemical level of organization, including definitions of key concepts in chemistry.

Matter

Anything that has mass and takes up space.

Define mass. How is it different from weight?

Mass = amount of matter in an object. Weight = depends on gravity.

Element

Pure substance made of only one type of atom.

Atom

The smallest unit of an element that retains its properties.

List the 3 subatomic particles with charge and location.

1. Protons: + charge, nucleus
2. Neutrons: neutral, nucleus
3. Electrons: – charge, orbit nucleus

What does the atomic number represent?

Number of protons.

What is atomic mass?

Protons + neutrons.

What are isotopes? Example?

Same element with different numbers of neutrons (e.g., Carbon-12, -13, -14).

What are radioactive isotopes used for?

PET scans, cancer treatment.

Define compound. Example?

Substance with 2+ different elements chemically bonded (e.g., NaCl, H₂O).

Define molecule. Example?

Two or more atoms bonded (can be same element, e.g., O₂).

Glucose (C6H{12}O_6) contains which elements?

Carbon, hydrogen, oxygen.

Radiology

Use of radiation in medical imaging/treatment.

Pros and cons of isotopes in medicine?

Pros: diagnostic imaging, targeted therapy. Cons: radiation damage, strict training needed.

Valence Electrons

Electrons in outer shell; determine reactivity.

What are the 3 main types of chemical bonds?

Ionic, covalent, hydrogen.

How are ionic bonds formed?

By transfer of electrons → atoms become charged ions.

Define cation vs anion. Example?

Cation = lost e^-, + charge (K^+). Anion = gained e^-, – charge (Cl^-).

Example of ionic bond compound?

NaCl (table salt).

How are covalent bonds formed?

By sharing of electrons.

Strongest type of bond?

Covalent bond.

Polar vs nonpolar covalent bonds? Examples?

Polar = unequal sharing (H2O). Nonpolar = equal sharing (O2, CH_4).

Why is water polar?

Oxygen is more electronegative → unequal electron distribution.

Hydrogen bonds

Weak attractions between polar molecules.

Importance of hydrogen bonds in biology?

DNA base pairing, protein folding, water cohesion.

Example of hydrogen bonding in everyday life?

Between H_2O molecules in a glass of water.

How does electronegativity trend across the periodic table?

Increases left → right.

Matter

Anything that has mass and takes up space.

Define mass. How is it different from weight?

Mass = amount of matter in an object. Weight = depends on gravity.

Element

Pure substance made of only one type of atom.

Atom

The smallest unit of an element that retains its properties.

List the 3 subatomic particles with charge and location.

1. Protons: + charge, nucleus
2. Neutrons: neutral, nucleus
3. Electrons: – charge, orbit nucleus

What does the atomic number represent?

Number of protons.

What is atomic mass?

Protons + neutrons.

What are isotopes? Example?

Same element with different numbers of neutrons (e.g., Carbon-12, -13, -14).

What are radioactive isotopes used for?

PET scans, cancer treatment.

Define compound. Example?

Substance with 2+ different elements chemically bonded (e.g., NaCl, H_2O).

Define molecule. Example?

Two or more atoms bonded (can be same element, e.g., O_2).

Glucose (C6H{12}O_6) contains which elements?

Carbon, hydrogen, oxygen.

Radiology

Use of radiation in medical imaging/treatment.

Pros and cons of isotopes in medicine?

Pros: diagnostic imaging, targeted therapy. Cons: radiation damage, strict training needed.

Valence Electrons

Electrons in outer shell; determine reactivity.

What are the 3 main types of chemical bonds?

Ionic, covalent, hydrogen.

How are ionic bonds formed?

By transfer of electrons → atoms become charged ions.

Define cation vs anion. Example?

Cation = lost e^-, + charge (K^+). Anion = gained e^-, – charge (Cl^-).

Example of ionic bond compound?

NaCl (table salt).

How are covalent bonds formed?

By sharing of electrons.

Strongest type of bond?

Covalent bond.

Polar vs nonpolar covalent bonds? Examples?

Polar = unequal sharing (H2O). Nonpolar = equal sharing (O2, CH_4).

Why is water polar?

Oxygen is more electronegative → unequal electron distribution.

Hydrogen bonds

Weak attractions between polar molecules.

Importance of hydrogen bonds in biology?

DNA base pairing, protein folding, water cohesion.

Example of hydrogen bonding in everyday life?

Between H_2O molecules in a glass of water.

How does electronegativity trend across the periodic table?

Increases left → right.

Define kinetic energy.

Energy of motion.

Define potential energy.

Stored energy.

Define chemical energy. Example?

Energy stored in bonds (ATP).

Define mechanical energy.

Movement of objects (muscle contraction).

Define radiant energy.

Light energy.

Define electrical energy. Example?

Flow of charged particles (nerve impulses).

Synthesis reaction formula and definition?

A + B → AB (anabolic, building).

Decomposition reaction formula and definition?

AB → A + B (catabolic, breaking down).

Exchange reaction formula?

AB + CD → AD + CB.

Reversible reaction symbol?

A + B ⇌ AB.

Factors that affect reaction rates?

Particle size/surface area, temperature, concentration/pressure, catalysts/enzymes.

Why is water the universal solvent?

Its polarity allows it to dissolve hydrophilic substances.

What is hydrolysis?

Breaks polymers with water.

What is dehydration synthesis?

Builds polymers by removing water.

Define solution, solvent, solute.

Solution = solvent + solute. Solvent dissolves, solute gets dissolved.

Define molarity.

Moles of solute per liter of solution.

Define colloid. Example?

Medium particles, don’t settle (milk).

Define suspension. Example?

Large particles, settle over time (blood).

What do salts form in water?

Electrolytes (Na^+, Cl^-, K^+).

pH < 7 = ? pH > 7 = ?

Acid; Base.

Human blood pH range?

~7.35–7.45 (slightly basic).

What stabilizes pH? Example?

Buffers, e.g., bicarbonate buffer system.

pH of stomach acid?

~1–2 (very acidic).

Strong acid vs weak acid example?

HCl = strong (fully dissociates). H3PO4 = weak (partially dissociates).

What elements do organic compounds always contain?

Carbon & hydrogen.

Why can carbon form diverse molecules?

It has 4 covalent bonds.

Hydroxyl (–OH) found in?

Carbohydrates.

Carboxyl (–COOH) found in?

Amino acids, fatty acids.

Amino (–NH_2) found in?

Proteins.

Methyl (–CH_3) does what?

Modifies molecule activity.

Phosphate (–PO_4^{2-}) found in?

ATP, nucleic acids.

General formula of carbohydrates?

C6H{12}O_6 (1C:2H:1O).

Examples of monosaccharides?

Glucose, fructose.

Examples of disaccharides?

Maltose, sucrose.

Examples of polysaccharides?

Starch, glycogen, cellulose.

How are carbs stored in humans?

Glycogen.

Main function of carbohydrates?

Fuel for ATP production.

Are lipids hydrophobic or hydrophilic?

Hydrophobic (nonpolar).

Structure of triglycerides?

Glycerol + 3 fatty acids.

Difference between saturated and unsaturated fats?

Saturated = solid (animal fats); Unsaturated = liquid (plant oils).

What are trans fats?

Artificially hydrogenated, harmful.

Structure of phospholipids?

Amphipathic (polar head, nonpolar tails).

Why are phospholipids important?

Make up cell membranes.

What are steroids? Examples?

4-ring structures (cholesterol, hormones).

Monomers of proteins?

Amino acids (20 types).

What bonds hold amino acids together?

Peptide bonds (covalent).