ch 10: modern atomic theory and the periodic table

electromagnetic radiation

form of energy that runs a continuum from radio to x-rays, visible light to microwaves

wavelength

distance between consecutive peaks/troughs of wave

wavelength

λ

frequency

v

frequency

number of times a wave passes through a certain point/second

speed

how fast a wave moves through space

electromagnetic spectrum

full range of radiation arranged based on wavelength

electromagnetic radiation

has both wave-like and particle properties

photons

radiation can behave like tiny packets of energy

bohr atom

suggested electrons exist in specific regions at defined distances from the nucleus

bohr atom

electrons move about nucleus in circular orbits at a fixed distance from nucleus

quantized

has discrete fixed units

bohr atom

suggested energy absorbed or emitted by an atom is quantized

ground state

lowest energy level for an atom

color of light emitted

depends on gap between energy levels

quantum mechanics

deal in electron probabilities

orbitals

orbits from bohr theory replaced by…

orbitals

regions of space with a high probability of finding an electron

principal energy level

n

principal energy level

provides a general idea of distance of an electron from nucleus

principal energy level

as this increases, so does distance from nucleus

principal quantum level n=1

electron has 90% probability of being located in orbital

principal quantum level n=1

spherical in nature

pauli exclusion principle

an atomic orbital can hold two electrons, which must have opposite spins

electron spin

represented by arrows

principal quantum level n=2

contains 2 sublevels/orbitals

2s orbital

spherical but larger and higher in energy

px, py, pz

2p orbitals

6

total electrons that can occupy 3 p orbitals of n=2 subshell

principal quantum level n=3

contains 3s, 3p, 3d orbitals

10

total electrons that can occupy 5 d orbitals of a subshell

3d

orbitals that have unique shapes relative to s/p orbitals

valence electrons

located in highest energy orbitals of atom

period number

corresponds to highest principal quantum number n of the elements

group numbering

by numbers 1-18 w numbers/letters

representative elements

A group

transition elements

B group

valence electron

all elements in a group have similar configurations

similar reactivity

elements in a group often have this as a result of similar valence electron configurations