Adv. Chem. Midterm

moles

unit of measurement represented by "n"

molar mass

the mass of one mole of a pure substance

periodic table

an arrangement of elements in which the elements are separated into groups based on a set of repeating properties

avogadro's number

number of representative particles in a mole, 6.02 X 10^23

atoms

smallest unit of matter

isotopes

Atoms of the same element that have different numbers of neutrons

average atomic mass

weighted average of the atomic masses for the isotopes of an element

solid

Definite shape and volume

liquid

the state of matter that has a definite volume but not a definite shape

gas

A state of matter with no definite shape or volume

formula units

the lowest whole-number ratio of ions in an ionic compound

empirical formula

a chemical formula showing the ratio of elements in a compound rather than the total number of atoms

homogeneous mixture

A mixture in which substances are evenly distributed throughout the mixture

heterogeneous mixture

A mixture in which different materials can be distinguished easily

chromatography

A laboratory technique used to separate mixtures of molecules

electron configurations

the arrangement of electrons in an atom

dalton's theory

all matter is made up of individual particles called atoms, which cannot be divided

coulomb's law

The relationship among electrical force, charges, and distance: The electrical force between two charges varies directly as the product of the charges and inversely as the square of the distance between them.

the bohr model

model of the atom in which electrons move rapidly around the nucleus in paths called orbits

the aufbau principle

An electron occupies the lowest-energy orbital that can receive it

the pauli exclusion principle

states that a maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins

hund's rule

states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals

noble gas shortcut

A shorthand way to write electron configurations. Write the noble gas followed by the rest of the electron configuration that follows the noble gas.

valence electrons

Electrons on the outermost energy level of an atom

core electrons

inner electrons

ionization energy

the energy required to remove an electron from an atom

atomic radius

size of an atom

nuclear charge

the total charge of all the protons in the nucleus

electron

A subatomic particle that has a negative charge

electron repulsion

A repulsive force caused by the similar negative charge of two or more electrons.

ionic radius

Distance from the center of an ion's nucleus to its outermost electron

electronegativity

the ability of an atom to attract electrons when the atom is in a compound

metal

an element that is shiny and that conducts heat and electricity well

nonmetal

an element that conducts heat and electricity poorly

polar covalent bonds

unequal sharing of electrons

nonpolar covalent bonds

equal sharing of electrons

cation

A positively charged ion, smaller than neutral

anion

A negatively charged ion, larger than neutral

dimensional analysis

A way to analyze and solve problems using the units, or dimensions, of the measurements

lewis dot structure

diagram of a molecule using dots to represent valence electrons

VSEPR

Valance Electron Pair Repulsion model / Unshared electron pairs around the central atom

Covalent

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Ionic

transfer of electrons

metallic bond

a bond formed by the attraction between positively charged metal ions and the electrons around them

resonance

the bonding in molecules or ions that cannot be correctly represented by a single Lewis structure

polarity

Molecules having uneven distribution of charges

dipoles

positive and negative charged ends of a polar covalent molecule

Planck's Constant

6.626 x 10^-34

Wavelength

The distance between two corresponding parts of a wave

Frequency

the number of complete wavelengths that pass a point in a given time

extensive property

a property that depends on the amount of matter in a sample

intensive property

a property that depends on the type of matter in a sample

half life

length of time required for half of the radioactive atoms in a sample to decay

molecular formula

A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms. The real number of atoms/elements needed to form compound.

mole highway

Grams --> Mole : Mass/Molar Mass \n Mole --> Atom : Mole # x 6.02E23 \n Atom --> Mole : Mole #/6.02E23 \n Mole --> Grams : Mass x Molar Mass

heating curve

a diagram that shows the temperature changes and changes of state of a substance as it is heated; Solid melts to liquid, liquid evaporates to gas. Gas condenses to liquid, liquid freezes to solid

Significant Figure Rules

1. non-zeros are always significant;
2. zeros between two other sig figs are significant;
3. all final zeros after the decimal point are significant;
4. zeros used solely for spacing the decimal point are not significant unless a decimal point is present

alkali metals

Group 1, 1 electron in outer level, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium

alkaline metals

metallic elements in group 2 of the periodic table which are harder than the alkali metals and are also less reactive

halogens

Contains nonmetals, 7 valence electrons in it's outermost energy level. Very reactive

noble gases

Elements in group 8A of the periodic table. Have no charge and are gases under normal conditions. (Helium, Neon, Argon, Krypton, Xenon, Radon)

octet rule

States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons

octet rule exceptions

\-Hydrogen (has only 2) \n -Lithium, Beryllium, and boron (less than 8) \n -all period 3 and below can hold >8

molecular shapes

Linear, Bent (lone pairs) , Trigonal Planar, and Trigonal Pyramidal (lone pair)