Chemistry: An Atoms Focused Approach Chapter 2

Subatomic Particles

the neutrons, protons, and electrons in an atom

Rutherford Experiment and Result

Gold Foil Experiment, Fluorescence Experiment; Nuclear Atom

Thomson Experiment and Result

Cathode Ray Tube Experiment (deflections by electric and magnetic fields); e/m = 1.7588196 x 10^11 Ckg^-1

Cathode Rays

streams of electrons emitted by the cathode in a partially evacuated tube

Electron

a subatomic particle that has a relative charge of -1 and essentially zero mass

Ion

an atom or molecule that has a positive or negative charge

Cation

a positively charged ion

Anion

a negatively charged ion

Millikan Experiment and Result

Oil Drop Experiment; e = 1.6021773 x 10^-19 C and
m = 9.109390x10^-31 kg

Thomson

Plum pudding model of atom and Determined e/m for electrons

Becquerel

Discovered radioactivity

Chadwick

Discovered nuetron

Rutherford

Predicted nuetron's existence

Millikan

Measured electron charge

Radioactivity

the spontaneous emission of high-energy radiation and particles by materials

beta particle

a radioactive emission that is a high-energy electron

alpha particle

a radioactive emission with a charge of 2+ and a mass equivalent to that of a helium nucleus

Atomic Mass Unit (amu)

unit used to express the relative masses of atoms and subatomic particles that is exactly 1/12 the mass of 1 atom of carbon with 6 protons and 6 neutrons in its nucleus

Dalton (Da)

a unit of mass equal to 1 atomic mass unit

Isotope

atoms of an element containing the same number of protons but different numbers of neutrons

Nuclide

a specific isotope of an element

Atomic Number (Z)

the number of protons in the nucleus of an atom

Nucleon

a proton or neutron in a nucleus

Mass Number (A)

the number of nucleons in an atom

Period

a row of elements in the Periodic Table

Group or Family

a column of the Periodic Table

Radionuclide

a radioactive (unstable) nuclide

Halogen

an element in group 17

Alkali Metal

an element of group 1

Alkaline Earth Metal

an element in group 2

Metals

elements that are typically shiny, malleable, ductile solids that conduct heat and electricity well and tend to form positive ions

Nonmetals

elements with properties opposite those of metals, including poor conductivity of heat and electricity

Metalloids or Semimetals

elements that tend to have the physically properties of metals and the chemical properties of nonmetals

Main Group Elements or Representative Elements

the elements in groups 1, 2, and 13 through 18

Transition Metals

the elements in groups 3 through 12

Noble Gases

the elements in group 18

Average Atomic Mass

the weighted average of masses of all isotopes of an element, calculated by multiplying the natural abundance of each isotope by its mass in amu and then summing the products

Natural Abundance

the proportion of a particular isotope, usually expressed as a percentage, relative to al the isotopes of that element in a natural sample

Molecular Mass

the mass in amu of one molecule of a molecular compound

Formula Unit

the smallest electrically neutral unit of an ionic compound

Formula Mass

the mass in amu of one formula unit of an ionic compound

Mole (mol)

an amount of a substance that contains Avogadro's Number (6.022 x 10^23) of particles (atoms, ions, molecules, or formula units)

Avogadro's Number

the number of carbon atoms in exactly 12 grams of the carbon-12 isotope (6.022 x 10^23). The number of particles in one mole.

Molar Mass (mew)

the mass of 1 mole of a substance

Quarks

elementary particles that combine to form neutrons and protons

Nuecleosynthesis

the natural formation of nuclei as a result of fusion and other nuclear processes

Mass Defect

the difference between the mass of a stable nucleus and the masses of the individual nucleons that comprise it

Binding Energy (BE)

the energy that holds the nucleons together in a nucleus

Strong Nuclear Force

the fundamental force of nature that keeps quarks together in subatomic particles and nucleons together in atomic nuclei

Neutron Capture

the absorption of a neutron by a nucleus

Beta Decay

the process by which a neutron in a neutron-rich nucleus decays into a proton and a beta particle

Beta Decay example

59 over 26 Fe -> 59 over 27 Co + 0 over -1 beta