CH 2 vocab

The smallest unit that retains the chemical and physical properties of an element

Pure substance that cannot be broken down into simper substances by ordinary chemical or physical means

positive charged subatomic particle (has mass)

no charge subatomic particle (has mass)

negatively charged subatomic particle (has relatively no mass)

The region of space when the electrons "live" most of the time

• regions of space around the nucleus where electrons are found.
• Shows the number of electrons in each orbital or just the valence electron shell

An electron in the outer-most energy level of an atom

A distinct form of the atoms of an element, with the same number of protons but different number of neutrons

A unit composed of atoms combinded chemically in fixed numbers and ratios

Link formed when atoms of reactive elements combine into molecules

A positive or negative charged atom

Bond that results from electrical attractions between atoms that have lost or gained electrons

• nonpolar covalent bonds have electrons shared equally
• -characteristics of molecules that contain atoms of 1 element
• polar covalent bonds share electrons unequally
• -atom attracts electrons more strongly

The measure of an atom's attraction for the electrons it shares in a chemical bond with another atom

• The name of a molecule written in chemical shorthand
• Ex. H2O

Noncovalent bond formed by unequal electron sharing between hydrogen atoms and oxygen, nitrogen, or sulfur atoms

weak molecular attractions over short distances

nonpolar substances that are excluded by water and other polar molecules

Polar molecules that associate readily with water

The high resistance of water molecules to separation

the adherence of molecules to the walls of conducting tubes, as in plants

• The force that places surface water molecules under tension, making them more resistant to separation than underlying water molecules
• Ex. When you do a bellyflop, you slap the water and you don't just fall through as if you were diving.

The water in a solution in which the hydration layer prevents polar molecules or ions from reassociating

A reaction that occurs when atoms or molecules interact to form new chemical bonds or break old ones

The atoms or molecules entering a chemical reaction

An atom or molecule leaving a chemical reaction