Chemistry: An Atom Focused Approach - CH 3: Atomic Structure

electromagnetic radiation

any form of radiant energy in the electromagnetic spectrum

electromagnetic spectrum

a continuous range of radiant energy that includes gamma rays, x-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, and radio waves.

visible light

colors of light shown as ROYGBIV where R is lower frequency, longer wavelength, and low energy and V is the opposite.

Maxwell's Theory

electromagnetic radiation moves through space as waves with two perpendicular components: an oscillating electric field and an oscillating magnetic field.

wavelength

The distance between two corresponding parts of a wave

frequency

the number of crests of a wave that passes a stationary point of reference per second. unit Hertz (Hz)

speed of light = 3.00 x 10^8 m/s =

wavelength X frequency

Fraunhofer lines

a set of dark lines in the otherwise continuous solar spectrum

quantum

the smallest discrete quantity of a particular form of energy

Energy of a photon equation

E=hc/wavelength or E=hv

photon

a quantum of electromagnetic radiation

quantum theory

a model based on the idea that energy is absorbed and emitted in discrete quantities of energy called quanta

threshold frequency

the minimum frequency of light required to produce the photoelectric effect

work function

the amount of energy needed to dislodge an electron from the surface of a material: = h x threshold frequency

kinetic energy of the electron equation

Ek = hv-work function

predicting wavelengths of hydrogen equation

1/wavelength = Rydberg Constant(1/nupper^2 - 1/nlower^2)

energy of an electron equation

-2.178X10^-18(1/n^2)

change in energy equation

ΔE= -2.178x10^-18 (1/nfinal^2 - 1/ninitial^2)

ground state

the most stable, lowest energy of a particle

excited state

any energy state above ground state

electron transition

movement of an electron between energy levels

DeBroglie equation

related the wavelength of any moving object to its mass and speed: wavelength = h/mu

Heisenberg uncertainty principle

it is impossible to know exactly both the velocity and the position of a particle at the same time

quantum mechanics

a mathematical description of the wavelike behavior of electrons and other particles

orbitals

defined by the square of the wave function; regions in an atom where the probability of finding an electron is high

quantum number

one of four related numbers that specify the energy, shape, and orientation of orbitals in an atom and the spin orientation of electrons in the orbitals

principle quantum number (n)

a positive integer describing the relative size and energy of an atomic orbital or group of orbitals in an atom

angular quantum number- L

symbolized by l, indicates the shape of the orbital

magnetic quantum number Ml

symbolized by m, indicates the orientation of an orbital around the nucleus

spin quantum number ms

either +1/2 or -1/2, indicating the spin orientation of an electron

the s orbital and ml=0

n=1, l=0

the p orbital and ml= -1,0,1

n=2, l=1

the d orbital and ml=-2,-1,0,1,2

n=3, l=2

the f orbital and ml=-3,-2,-1,0,1,2,3

n=4, l=3

Pauli Exclusion Principle

no two electrons in the same atom can have the same set of four quantum numbers

s orbitals

spherical shape

p orbitals

dumbbell shaped (Px,Py,Pz)

d orbitals

four leaf clover shape

Aufbau Principle

the concept of building up ground state atoms so that their electrons occupy the lowest energy orbitals availible

electron configuration

the arrangement of electrons in the orbitals of an atom

core electrons

electrons that fill inner shells in an atom or ion. not involved in chemical reactions

valence electrons

electrons in the outermost occupied shell of an atom, having the most influence on the atom's chemical behavior

valence shell

the outermost occupied shell of an atom

degenerate

orbitals with the same energy

Hund's Rule

the lowest energy electron configuration of an atom has the maximum number of unpaired electrons, all of which have the same spin, in degenerate orbitals

orbital diagram

a depiction of the arrangement of electrons in an atom or ion using boxes to represent orbitals

isoelectric

describes atoms or ions that have identical electron configurations (ex: Na+, F-, and Ne)

paramagnetic

one or more unpaired electrons, attracted to magnetic field

diamagnetic

All electrons are paired; slightly repelled by a magnetic field.

increase

as we go down a group of elements in the periodic table, size of atoms

decrease

as we move from left to right across a row of the periodic table, size of atoms

smaller

cations are ___ than their parent atoms

larger

anions are ____ than their parent atoms

ionization energy (IE)

the amount of energy needed to remove 1 mole of electrons from 1 mole of ground-state atoms or ions in the gas phase

electron attachment enthalpy

the energy change that occurs when 1 mole of electrons combines with 1 mole of atoms or ions in the gas phase

decrease

Metallic behavior tends to ___________ as you move from left to right across a period

increase

Metallic behavior tends to _____________ as you move from the top to the bottom of a family