HChem Unit 2 Test

i don't want to study. it sucks. but it doesn't suck as much as failing does.

John Dalton

atomic theory & solid sphere atom model

J.J. Thomson

Cathode Ray Tube & plum pudding model atom

Rutherford

Gold Foil Experiment & nuclear atom model

Millikan

Oil Drop Experiment

bohr

planetary model (modified rutherford’s model)

schrodinger

widely accepted today

light is a type of

electromagnetic radiation (travels through space as a wave)

wavelength and frequency are

indirectly related

Frequency symbol

v

frequency is measured in

Hz

Wavelength symbol

upside down Y

wavelength is measured in

m

electromagnetic spectrum

ROYGBIV

low to high energy (red to violet, 750nm to 400nm)

radio, microwave, infrared, ultraviolet, xray, gamma ray (low frequency to high frequency)

wavelength is

the distance between wave crests

amplitude

distance from origin to top of crest

crest is

the highest part of a wave

trough is

the lowest part of the wave

long wavelength =

low frequency

frequency is

how fast a wave oscillates, number of wavelengths per second

wave speed symbol

C

wavespeed is measured in

m/s

Wave speed formula:

C = 3.00 × 10^8 m/s

C is the

speed of light

Formula to find the difference between wavelength and frequency:

ROYGBIV combines to form

white light

continuous spectrum is produced by

dense gases or solid objects which radiate heat

emmision spectrum is

when only Specific wavelengths of light are emitted by a hot gas

neils bohr developed

a model for the atom that explained the atomic spectra (only worked for hydrogen)

a photon is

smallest amount/quantum of electromagnetic radiation, the basic unit of all life

Ephoton = h x v

plank’s constant (h) = 6.626 × 10^-34 J x s

ground state

n=1

excited states

n=2 or up

emission is when

the state decreases

excitation is when

ground state increases

energy of an electron

KNOW ALL EQUATIONS

Quantum Mechanical Model

most accurate model of atom

Einstein’s Photoelectric Effect

 a beam of light is a swarm of discrete energy packets/photons

Louis de Broglie

tried to find another model because bohr’s model only worked for hydrogen and failed for larger atoms. Broglie said electrons behave with wave properties.

Heisenberg’s Uncertainty Principal

impossible to know both the position and momentum of an electron

electron configuartion

form of notation that shows how the electrons are distributed among the atomic orbitals and energy levels

what are energy levels

regions of space around the nucleus defining location of e-

what are sublevels?

what are orbitals

more exact areas of space, more likely to find electrons there (s, p, d, f)

s orbital

can hold 2 e-

p orbitals

can hold upto 6 e- total

d orbitals

hold upto 10 e- total

f orbitals

hold upto 14 e- total

aufbau principal

pauli exclusion principal

what is an electron spin? (three things)

paramagnetic is

unpaired electrons, causes atoms to be attracted to magnets

dismagnetic is

paired electrons, atoms are not attracted to magnets

hund’s rule

blocks on periodic table

s, d, p, (f is bottom)

orbital filling diagrams

electron configuration exceptions

valence electrons are

lewis dot diagram

Atomic Radius

gets bigger as you go down a group

Coulomb’s Law

Zeff is

Effective Nuclear Charge

Effective Nuclear Charge formula is

Atomic size increases as the

as thprincipal quantum number (n) increases

atomic size decreases as the

effective nuclear charge (Zeff) increases

for main group elements, atomic size increases when

going down a group decreases across a period

cations

losing e-, smaller than the parent atom, losing e- causes the Zeff to increase and the remaining e- experience a greater attraction to the nucleus

anions

gaining e-, larger than parent ion, adding electrons to a neutral atom causes electron to electron repulsion

ionization energy is

energy required to remove a valence electron from an atom (KJ/mol)

the larger the nuclear charge,

the greater the ionization energy

the greater the sheilding effect,

the less ionization energy

the greater the radius between the nucleus and the valence shell,

less ionization energy

an electron from a full of half-full sublevel requires

additional energy to be removed

Know & Undertstand:

anomalies across a period:

All 3 trends

Metalic properties

conductivity and malleability, depend on having electrons that can be removed easily, metallic character increases as we move down a group, metalic character decreases across a period like atomic size because it is easier to remove an electron that is farther away from the nucleus.

electronegativity is

a measure of the tendency of atom to attract a bonding pair of electron

What are the three subatomic particles?

Protons, Neutrons, and Electrons

The center of an atom is called what?

Nucleus

What are the charges of the subatomic particles?

Proton is positive one, Neutron is neutral, Electron is negative one

particle mass is

protons + neutrons

number of protons and neutrons are

the same

most abundant isotope of an element is

the atomic mass

COULUMBS LAW formULA

WHY does the ATOMIC RADII DECREASE as the atomic numbers increase in a period

greater effective nuclear charge (Zeff), increases attractive force of the nucleus which pulls the electron cloud closer to the nucleus and results in a smaller atomic radius

WHY does ATOMIC RADII INCREASE as atomic number increases down a column/group

Increased number of energy levels increases the distance over what the nucleus must attract and reduces the attraction of electrons, full energy levels provide shielding in between the nucleus and valence electrons causing Zeff to be somewhat constant

WHY does IONIZATION ENERGY INCREASE when the atomic number increases in a period

because Zeff increases the attractive force of the nucleus and causes the electrons to be held more tightly, the exception between groups 2-3 is because a drop in the IE occurs and the p electrons dont penetrate the nuclear region as much as the s electrons ad arent held as tightly, the exception between 4-5 groups are because IE drops due to the fact that the increased repulsion created by the first electron pairing in the p-orbitals and outweighs the increase in Zeff making less energy required to remove an electron

WHY does IONIZATION ENERGY DECREASE as atomic number increases down a column

Increased number of energy levels (n) increases the distance that the nucleus must pull and reduce the Coulombic/electrostatic attraction of electrons. Full energy levels provide shielding between the nucleus and valence electrons cauing the Zeff in a group to be somewhat constant.

Electron affinity is

NOT the opposite of ionization energy. It involves the addition of an electron to a gaseous atom which can be exothermic or endothermic. Exothermic value indicates that the resulting negative ion is stronger and attracts the electron more effectively. positive electrons indicate that the nucleus isnt as effective at attracting electrons and that it must be forced into the atom.

Electronegativity is

the assigned property that indicates the attraction of an atom for the pair of outer shell electrons in a covalent bond with another atom. Electronegativity patterns are the same as electron affinity patterns because both of these properties focus on the attraction that the nucleus has for electrons.

ELECTrONEGATIVITY INCREASES with the atomic number in any period because

Zeff increases the attractive force of the nucleus and strengthens the attraction for the electrons

ELECTRONEGATIVITY DECREASES as the atomic number increases down a group

n increases the distance over which the nucleus must pull and reduce the attraction for electrons. Full energy levels provide shielding between the nucleus and valence electrons so in a group Zeff is somewhat constant.

Ionic radius is

the distance from the nucleus to the outer edge of the electron cloud in a charged ion.The same radii trends apply when you divided the table into the metal and nonmetal sections. WIthin the metal section, the positive ionic radii decreases from left to right with minor changes in the transition metals. Once you get to the nonmetal section and the ions are now large and negative they will decrease in radii from left to right. Ionic radii increases going down all groups because of the additional energy levels present.

Positive ions are smaller than their respective neutral atoms because

Negative ions are larger than their respective neutral atoms because

Metals are more reactive moving down a group because

Non-metals are more reactive as you move up a group because

Know all trends: