Chemistry – First Semester Terms Flashcard

the measure of matter in an object
anything that has mass and takes up space
the smallest unit of an element that maintains the chemical identity of that element
a pure substance that cannot be broken down into simpler, stable substances
a substance made up of atoms from two or more elements joined by chemical bonds
physical property
a characteristic that can be observed or measured without changing the identity of the substance
physical change
a change that does not involve the change in the identity of the substance
chemical property
substance’s ability to undergo changes to transform it into different substances
chemical change
a change that turns a substance into an entirely different substance
change of state
a physical change of a substance from one state to another
something that has a definite shape and a definite volume
something that has no definite shape but has a definite volume
something that has neither a definite shape or volume
pure substance
a fixed composition that has exactly the same characteristic properties and has exactly the same composition
a blend of two or more kinds of matter that can either be homogeneous or heterogeneous
uniform in composition
un-uniform in composition
a vertical column of elements in the periodic table (see family)
a vertical column of elements in the periodic table (see group)
a horizontal row of elements in the periodic table
elements that are good conductors of heat and electricity
elements that are poor conductors of heat and electricity
how close the value is to the true or accepted value
how reproducible the same value is
an element that has the same number of protons but different number of neutrons
mass number
equal to the number of protons plus the number of electrons
atomic mass unit
a unit used for expressing masses in atoms or molecules
a counting number for atoms
Avogadro’s number
(6.0221 x 10(^23) atoms / 1 mole
molar mass
grams of element (an average) / mole
ground state
the lowest energy state of an atom or particle in its most stable state (neutral, no charge)
excited state
an atom or partial with a charge
holds electrons in shells
electron configuration
using numbers and letters, no indication of spin.
ex: 1s(^2), 2s(^2), … etc
Aufbau principle
an electron occupies the lowest energy orbital that can receive it
Pauli exclusion principle
no more than two electrons in each drawer. when you have two electrons in the same drawer, they have to have different spins
Hund’s rule
orbitals of equal energy are filled by placing a single electron in each orbital and then doubling up after that. when single electrons are placed in orbitals of equal energy, they must have the same spin state
charged atoms
when atoms give up electrons (form cations)
ionization energy
the energy required to remove an electron from an atom
electron affinity
when atoms gain electrons (forms anions)
a positive ion
a negative ion
valence electrons
electrons that are available for bonding
measure of the ability of an atom to attract electrons from other atoms (there is no transfer of electrons! it’s how badly an element wants an electron!)
chemical bond
ionic bonding
metal to nonmental bonding (transferring)
covalent bonding
nonmental to nonmetal bonding (sharing)
nonpolar covalent bonding
structure type for COVALENT bonds (this vs ionic compounds)
polar covalent bonding
molecular compound
a chemical compound where the simplest units are molecules
molecular formula
a formula that shows the number of atoms in a molecule
electron-dot notation
way to show an element with its valence electrons
Lewis structure
way to show bonds between COVALENT bonding
structural formula
a formula that indicates the location of atoms, number of bonds, and location of bonds
ionic compound
structure type for IONIC bonds (this vs molecules)
formula unit
a ratio of atoms – for IONIC bonding
ex. NaCL, MgO, LiBr
lattice energy
the energy that holds the atoms together in an ionic compound
metallic bonding
metal to metal bonding

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