BIO 1120 Week 2

Matter

Anything that takes up space and has mass.

Elements

Unique chemical and physical properties that cannot be broken down into smaller units.

Common Elements

Oxygen, carbon, hydrogen, and nitrogen are the most common elements found in living organisms.

Atom

The smallest unit of mass that contains the chemical properties of an element.

Nucleus

The part of an atom that contains protons and neutrons.

Electrons

Negatively charged particles found in a cloud beyond the nucleus of an atom.

Proton Mass

Approximately 1.67x10^-24g.

Neutron Mass

Approximately 1.67x10^-24g.

Electron Mass

Approximately 9.11x10^-28g.

Atomic Mass

The mass of an element considering only protons and neutrons.

Atomic Number

The number of protons in an atom.

Neutrons Calculation

Atomic number - mass number = number of neutrons.

Isotopes

Different forms of an element with the same number of protons but different numbers of neutrons.

Radioisotopes

Isotopes that attain a more stable electron configuration.

Chemical Reactivity

An element's ability to combine with others chemically.

Molecules

Consist of 2 or more atoms chemically bonded together.

Octet Rule

Atoms are most stable with 8 electrons in their valence shell (except the innermost shell).

Noble Gases

Group 18 elements known for their non-reactiveness due to 8 valence electrons.

Ions

Charged atoms formed after losing or gaining electrons.

Electron Orbitals

Complex shapes/paths where electrons are likely to be found.

1s Orbital

The closest orbital to the nucleus that can hold two electrons.

p Orbitals

Found in shapes of dumbbells, can hold up to 8 electrons in total with s orbitals.

Reactants

Substances at the beginning of a chemical reaction.

Products

Substances formed at the end of a chemical reaction.

Balanced Chemical Equations

Take into account the law of conservation of mass.

Compounds

Consist of more than one type of element.

Cations

Positive ions.

Anions

Negative ions.

Electron Transfer

The process of electrons moving from one atom to another.

Ionic Bonds

Occur between atoms of opposite charges.

Electrolytes

Salts needed for nerve impulse conduction, muscle contractions, and water balance.

Covalent Bonds

Occur when atoms share electrons to fulfill the octet rule.

Polar Covalent Bonds

Atoms share electrons unequally due to differences in electronegativity.

Water

A polar bent molecule with oxygen having higher electronegativity than hydrogen.

Nonpolar Covalent Bonds

Occur between elements of similar electronegativity.

Hydrogen Bonds

Responsible for many of water's properties and stabilizing proteins and DNA.

Van der Waals Interactions

Weak attractions between molecules dependent on electron density fluctuations.

Water's Properties

Include high heat capacity, high heat of vaporization, and ability to dissolve polar molecules.

Hydrophilic

Water-attracting molecules.

Hydrophobic

Molecules that do not mix well with water.

Ice Density

Ice is less dense than liquid water due to its crystalline structure.

Insulating Barrier

Ice protects life underwater by providing insulation.

Heat Capacity

The energy needed to increase 1 gram of a substance by one degree Celsius.

Heat of Vaporization

The energy required to transform 1 gram of a substance from liquid to gas.

Evaporation

Occurs below water's boiling point when surface molecules gain enough energy to vaporize.

Solvent

A solution that can dissolve a solute.

Spheres of Hydration

Form around molecules water is attracted to due to charge.

Dissociation

Occurs when an ionic compound dissolves in water, breaking into ions.

Cohesion

The ability of water molecules to stick to themselves.

Surface Tension

The capacity of a substance to withstand rupture under stress.

Adhesion

The attraction of water to other substances.

Capillary Attraction

The ability of water to move through narrow spaces.

pH Indicator

Litmus paper used to determine the pH of a substance.

Hydrogen Ions

Formed in pure water through dissociation.

Mole

The atomic weight of a substance equal to the number of atoms in 12 grams of carbon.

Acidic pH

Indicates more H3O+ ions.

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