Ch.2 Life's Chemical Basis

Front 1

Atoms

Back 1

Consist of protons, neutrons, and electrons

Front 2

Protons

Back 2

Positively charged subatomic particle that occurs in the nucleus of all atoms

Front 3

Electrons

Back 3

Negatively charged subatomic particle that occupies orbitals around an atomic nucleus.

Front 4

Neutrons

Back 4

Uncharged subatomic particle in the nucleus

Front 5

Charge

Back 5

Electrical property. Opposite charges attract and like charges repel

Front 6

Atomic number

Back 6

Number of protons in the atomic nucleus; determines the element

Front 7

Elements

Back 7

Pure substances that contain only atoms with the same number of protons

Front 8

Periodic table

Back 8

Tabular arrangements of the known elements by atomic number

Front 9

Isotopes

Back 9

Atoms of an element that differ in their number of neutrons; all elements have isotopes

Front 10

Mass number

Back 10

Total number is protons and neutrons in the nucleus of an atom

Front 11

Radioisotope

Back 11

Isotope with an unstable nucleus; decays at a constant rate into certain products

Front 12

Radioactive decay

Back 12

Process by which an isotope emit energy and/or subatomic particle when their nucleus spontaneously disintigrates; example: carbon 14's (6 protons 8 neutrons) neutron splits into a proton and electron causing it to become nitrogen 14 (7 protons, 7 neutrons)

Front 13

Tracer

Back 13

Any molecule with a detectable substance attached

Front 14

Shell Models

Back 14

Model of an electron distribution in an atom. Multilayered; electrons at the higher levels have more energy. Electrons can move to higher levels if an energy input gives it a boost, but immediately emits it's extra energy and moves back down

Front 15

Electron vacancy

Back 15

Vacancy in a shell. Atoms with vacancies tend to interact with atoms: they give up, acquire or share electrons until they have no vacancies in their outermost shell. Atoms are at their most stable state when it has no vacancies

Front 16

Ion

Back 16

Charged atom; positive charge when it loses an electron, negative charge when it pulls an electron away from another atom.

Front 17

Electronegativity

Back 17

Measure of an atoms ability to pull electons away from other atoms; not the same as a charge but depends on its size and how many vacancies it has

Front 18

Molecule

Back 18

Result of a chemical bond between two or more atoms with same or different elements

Front 19

Compounds

Back 19

Molecules that consist of two or more different elements

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Mixture

Back 20

Intermingling of two or more types of molecules/substance; No chemical bonds

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Chemical bond

Back 21

Attractive force that arises between two atoms when their electrons interact

Front 22

Solution

Back 22

Liquid mixture

Front 23

Ionic bond

Back 23

Strong mutual attraction of opposite charged ions

Front 24

Covalent bond

Back 24

Two atoms that share a pair of electrons: when sharing is equal, the bond is nonpolar, when one atom is exerting a greater pull, it's is polar

Front 25

Hydrogen bond

Back 25

Weak attraction between a covalent bonded hydrogen atom and another atom taking part in a separate polar covalent bond

Front 26

Solvent

Back 26

A substance, usually a liquid, that can dissolve other substances

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Solute

Back 27

Dissolved substance

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Salt

Back 28

Compound that dissolves easily in water and releases ions other than H+ and OH- when it does

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Hydrophilic

Back 29

A substance that dissolves easily in water, polar molecules because hydrogen bonds form between them and water molecules, pulling it's atoms apart; ex. Salt

Front 30

Hydrophobic

Back 30

A substance that resists dissolving in water; ex. Oil

Front 31

Polarity

Back 31

Any separation of charge into distinct positive and negative regions

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Cohesion

Back 32

Water molecules resist separating from one another

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Evaporation

Back 33

Transition of liquid to gas; resisted by hydrogen bonds

Front 34

Temperature

Back 34

Measure of molecular motion

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Concentration

Back 35

The amount of a particular solute that is dissolved in a given volume of fluid

Front 36

pH

Back 36

Measure of number of hydrogen ions in a fluid; H+ hydrogen = OH- hydroxide pH level is 7; the higher the number of hydrogen ions, the lower the pH level. Decrease in one-unit = tenfold increase of hydrogen ions: 0 = more acidic 14 = more basic

Hint 36

Front 37

Acids

Back 37

Give up hydrogen ions when dissolved in water

Front 38

Bases

Back 38

Substance that accepts hydrogen ions in water

Front 39

Buffer

Back 39

Set of chemicals that can keep the pH of a solution table by alternately donating and accepting ions that contribute to pH; ex. Base added to a buffered fluid causes the buffer to release H+ forming water which has no effect on pH