BIO103 Chapter 2

Matter

What makes up everything; can not be created or destroyed

Atoms

The smallest portions that contain each quality of what they make up

Electrons

The negatively charged portions of atoms

Protons

The positively charged parts of an atom

Neutrons

Neutrally charged parts of an atom

Atomic number

The number of protons, and almost always the number of electrons

Atomic mass

The amount of mass in an atom (mass is the measure of an object's resistance to acceleration when a net force is applied.)

Element

A substance that cannot be decomposed into simpler substances by chemical means, and is made up of atoms all with identical number of protons.

Isotopes

An atom where the amount of neutrons is different from the number of protons, changing the mass but not the chemical properties.

Radioactive Isotopes

An isotope that is unstable and gives off excess energy

Half-life

The time it takes for a substance to lose half its radioactive energy

Neutral atoms

An atom that has an equal amount of neutrons and protons

Ion

An atom that has a different number of electrons and protons

Cation

An ion that has a positive charge;

Anion

An ion that has a negative charge;

Orbital

Orbitals are the areas electrons through

Oxidation

Part of the redox reaction which loses charge (Loss of electrons)

Reduction

Part of the redox reaction that gains charge (Gain of electrons)

Energy level

A region of an atom where electrons of the same energy will be found

Valence electrons

The electrons in the outermost orbital

Inert

Lacking ability to move

Octet rule

When forming compounds, atoms will form the electron configuration of a noble gas- 8 valence

Molecule

A group of bonded atoms

Compound

Atoms of two+ elements joined by bonds

Chemical bonds

Attractive forces that hold atoms together

Ionic bonds

One+ electrons are transferred from one atom to another atom

Ionic compound

Compound composed of positive and negative ions

Covalent bonds

Bond created by sharing electrons

Double bonds

Sharing two pairs of electrons between two atoms

Single bonds

Sharing one pair of electrons between two atoms

Triple bonds

Sharing three pairs of electrons between two atoms

Structural formulas

Shows the structures of a compound

Molecular formulas

A chemical formula that shows the number and kinds of atoms in a molecule

Chemical reaction

Process that changes reactants to products

Reactants

Starting material of a chemical reaction

Products

The resulting material of a chemical reaction

Water

H2O; two hydrogen atoms bonded to a single oxygen

Electonegativity

How capable an atom is at attracting electrons

Polar molecules

Molecule that's electrons are shared inequally

Hydrogen bonds

Weak attraction between a hydrogen atom and another atom

Cohesion

A substance clinging to another substance- one of water's properties

Adhesion

A substance bonding to another substance- one of water's properties

Surface tension

Liquids are hard to break due to cohesion- surface tension is a measure of how hard the liquid is to break

Specific heat

The amount of heat it takes to heat a liquid

Heat of vaporization

The heat it takes to make a liquid into a gas

Hydrophobic

An aversion to water/avoiding water

Hydrophillic

An attraction to water/moving towards it

Hydrogen ion

Hydrogen atom that has lost an electron, H+

Hydroxide ion

Negatively charged ion, oxygen+hydrogen (OH-)

pH scale

How acidic or basic a substance is- how many hydrogen ions a substances has

Buffer

Compound that prevents sudden changes in pH

Non-polar covalent bond

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

Noble Gases

Stable with 8 valance electrons, in the last column of the periodic table.

Acid

A substance that increases the hydrogen ion (H+) concentration of a solution.

Base

A substance that increases the hydroxide ion OH- in a solution accepts hydrogens.