Module 6: Matter

Mass and energy are?

interchangable

E = ?

mC²

what does E stand for

energy in joules

what does C stand for

speed of light

• 3.0 × 10^8 m/second

m stnads for?

mass in kg

what does energy come in ?

many diff forms

• mechanical

• chemical

• nuclear

• heat

• electrical

• electromagnetic

mechanical energy?

movement

chemical energy

occurs during reactions

heat energy

increase of kinetic energy of particles

electrical energy

flow of electrons

nuclear energy

stored in nucleus

electromagnetic energy

photons traveling through space

what unit do we use for mass at atomic level

Daltons (Da)

what does 1 dalton equal

• 1 u or the mass of 1 prton

what does we use for energy instead of Joules

electron volts (eV)

what is 1 eV

the energy acquired by an electron as it is accelerated through 1 volt of electrical potential

1 eV = how many joules

1.60218 × 10^-19 kgxm²/sec²

1Kev =?

1,000 eV

1MeV =?

1,000,000 eV

mass deficit?

• the unaccounted for or lost mass

what causes mass deficit?

result of the mass that has been converted to energy which holds the atom together or what is called the nuclear binding energy

nuclear fission

• the splitting of atomic nuclei into smaller nuclear fragments

what is nuclear fusion

forcing together of smaller atomic nuclei to form a single larger nucleus

who coined the term radioactive

pierre and marie currie

what material were most commonly found to emit radiation

isotopes

the ground state

lowest possilbe energy state

what do all nuclei seek out

their ground state

what is the ground state defined by

the most ideal number of neutrons for that element

what makes an element unstable

too many or too few neutrons

what does an unstable nucleus release its excess energy in the form of

radiation

what form can radiation be

particles or waves

what is considered unstable

what the amount of energy required to hold the nucleus together is too much so it ejects particles to lower the binding energy needed

nuclear binding energy

• acts as glue which keeps an atom from falling apart

radioactive decay

an isotop that has an unstable nucleus spontaneously moving to a more stable state over time by releasing energy in a particle or electromagnetic

what are isotopes that undergo radioactive decay called

radioisotopes

radioisotope

isotope that is a radionuclide (radioactive)

radionuclide

atom that is radioactive

origin of many naturally occuring radioisotpes?

when earth was formed 4.6 billion years ago

how have isotopes remaining in earths crust formed?

• very slowly

• originally formed there

• or are members of 3 main decay seres from the original radionuclides

what happes when a stable form has been reached?

the decay cascade stops and no further change in nuclear structure

ways natrually occurnig radioisotopes form

• earth crust when it was made years ago

• or constant bombardment of the upper atmosphere from cosmic radiation

which form of naturally occruing isotope decays faster

• cosmic radiation

natural background radiation types

• cosmic radiation

• terrestrial radiation

• radon gas

• internal radiatno

what is cosmic radiation

• avg 30mR/year

• comes from outer space

• biggest source is the sun

what is terrestrial radiation

• avg 30mR/year

• comes from minerals in the ground

what is radon gas

• 100-200 mR/year

• product of decaying uranium

• it can seep up from the gorund and accumulate in homes

what is internal radiation

• avg 40 mR/year

• comes from radioisotopes that are stored in our body

what is process of artifically producing radioisotopes

• bombard stable nuclei with various particles

• either charged or uncharged resuling in new species

• adding or removing protons or neutrons form the targeted nuclei

what do larger nuclei tend to be?

less stable

what do nuclei with odd numbers of protons and odd numbers of neturons tend to be

less stable

nuclei with an even/odd raition of either proton/neutron or neutron/proton mix tend to be

more stable

nuclei with even/even ratio or protons/neutrons tend to be

most stable

why are more neutrons needed as nuclei get larger-

• bc more prtons are squished closer together

• needing more neutrons to keep the nucleus from falling apart

the amount of energy it takes to break a nucleus up into its seperate components

nuclear binding energy (Eb)

higher the avg value of Eb/A means

more stable the nucleus

transmutation

the change of a radionuclide into a differenet element by means or radiactive decay

how many can each orbital shell electrons can it hold

2n²

how many substates does each shell have

2n-1

what does lower shell have?

more tightly bound electrons because they are closer to the nucleus which has a strong postivie charge which attracts the electrons which have a negative charge

higher the “n” of a shell the?

most energetic the electrons are and thus are less tightly bound

what is orbital binding energy

the energy required to remove an electron from a given shell

order shells in binding energy from greatest to least

K>L>M>N

the great the Z the __ the binding energy

• greated

• because more postive charges as the number of protons in the nucleus increase

what is the energy required to move an electron from an inner shell to an outer shell

exactly equal to the difference in the shells binding enrgy

particulate radiation

• consists of atomic or sub atomic particles that carry energy in the form of kinetic energy

electromagnetic radiation

• energy carried by oscillating electric and magnetic fields in space at the speed of light or photons

what did max planck do

father of quantum theory

idea of quantom theory

idea that energy in atoms is found in distict packets of energy called quanta

wave

disturbance in any medium (such as water) which transports energy from one place to another without causingany permanent change in the medium

• exmaple: sound travels in air but not permanently chagne it

tranverse waves

displacement of the medium is perpendicular to the direction of wave travel

longitudial (compressional) waves

displacement of the medium is parallel to the firection of wave travel

transverse waves

longitudial waves

what is an example of longitudinal waves

sound waves

example of transverse waves

water waves

what are the 4 characteristics of all waves

• speed

• amplitude

• wavelength

• frequency

what is amplitude

maximum displacement of the medium

• height of water waves

• associated with how “strong” the waves are

amplitude inverse square law

• each doubling of the distance from the source the amplitude drops to one quarter of the original

wavelength

measured between two like points along the wave form

cycle

• one completion of the wave form (before it repeats itself)

• each cycle consists of two pulses, one negative and one positvie

frequency

number of cycles (waves) that pass by a given point each second

• measured in hertz

• 1Hz = 1 cycle/second

what does AM stand for

amplitude modulation

what does FM stand for

Frequency modulation

what is the wave formula

• v = f (lambda)

• velocity = frequency x wavelength

velocity and frequency are

directly porportional

velocity and wavelength are

directly proportional

frequency and wavelength are

inversely proportional

electromagnetic waves include?

radio and tv waves, radar, microwabes, infared light, visable light, ultraviolet light, x-rays, gamma rays, and cosmic rays

how to electromagnetic waves differ from water waves

• electromagnetic waves always travel at the same speed in a vacuum such as outer space

if one triples

the other must be cut to 1/3

planck formula

E = hf

what is h

• plancks constant a ocnversion factor between volts and hertz

how can you rewrite plancks formula for the relationship between energy and wavelenght

E = h/wavelength