TRI 1 HCHEM

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matter

anything that has mass and takes up space (volume)

atom

the smallest component of an element having the chemical properties of the element

ion

a particle that is electrically charged; an atom or molecule or group that has lost or gained one or more electrons

cation

a positively charged ion

molecule

a group of two or more atoms held together by attractive forces known as chemical bonds

valence electron

an electron in the outer shell of an atom which can combine with other atoms to form molecules

chemical property

a property used to characterize materials in reactions that change their identity

physical property

any property used to characterize matter and energy and their interactions

chemical change

happens when one chemical substance is transformed into one or more different substances

physical change

type of change in which the form of matter is altered but one substance is not transformed into another

anion

a negatively charged ion

electronegativity

the tendency of an atom or radical to attract electrons in the formation of an ionic bond

ionization energy

the amount of energy required to remove an electron from an isolated atom or molecule

pure substance

a material that has a constant composition (is homogeneous) and has consistent properties

homogeneous mixture

a mixture in which the composition is uniform throughout the mixture

heterogeneous mixture

a mixture in which the composition is not uniform throughout the mixture

solution

a homogeneous mixture of two or more substances; frequently a liquid solution

alkaline earth metal

any of the bivalent metals of group II of the periodic table

octet

the eight-electron arrangement in the outer electron shell of the noble-gas atoms

octet rule

the tendency of atoms to prefer to have eight electrons in the valence shell

isoelectronic

having the same numbers of electrons

metals

good conductors of heat + electricity, malleable, ductile, solids at room temperature, shiny appearance

non-metals

poor conductors of heat + electricity, brittle, dull in appearance, solids + gases at room temperature

metalloids

show characteristics of metals and non-metals, shiny but brittle, used in semi-conductor industry

coulombic attraction

the force of attraction between positive and negative charges

effective nuclear charge

the nuclear (+) charge experienced by the valence electrons

shielding effect

the presence of electrons in the inner shells reduces the hold of the nucleus on the outer (valence) electrons

noble gas

any of the chemically inert gaseous elements of the helium group in the periodic table ( non reactive + stable)

accuracy

the average of the readings is close to the actual value

precision

the values are close to each other (consisten)

atomic number

the order of an element in Mendeleyev's table of the elements; equal to the number of protons in the nucleus or electrons in the neutral state of an atom of an element

pauli exclusion principle

(1) no more than two electrons can occupy the same orbital and (2) two electrons in the same orbital must have opposite spins

Hund's rule

every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin

Aufbau Principle

electrons fill lower-energy atomic orbitals before filling higher-energy ones

excited state

electron temporarily occupies an energy state greater than its ground state

ground state

the state of lowest energy for that electron

visible spectrum

violet, indigo, blue, green, yellow, orange, red (high-low freq)

periodic law

the principle that chemical properties of the elements are periodic functions of their atomic numbers

atomic radii

the total distance from an atom's nucleus to the outermost orbital of electron

ionic radii

the distance between the nucleus of an ion and the outermost shell of the ion

akali metals

soft, shiny, very reactive, 1 valence electron

halogen

six nonmetallic elements that constitute Group 17

chemical bond

an electrical force linking atoms

ionic bond

a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion

mole

amount of substance

polyatomic ion

ions which consist of more than one atom

ionic compounds

compounds composed of ions

solute

the dissolved matter in a solution; the component of a solution that changes its state

alloy

substance that combines more than one metal or mixes a metal with other non-metallic elements

solvent

a liquid substance capable of dissolving other substances

density

d = m/v

wave equation

c = λv

energy equation

E = hv

Average Atomic Mass

MP+MP+MP... / 100

isotope

one of two or more atoms with the same atomic number but with different numbers of neutrons