ib unit 1

what is the nucleus of an atom like?

positively charged, has positive protons and neutral neutrons

what are the electrons of the atom like?

negatively charged, occupy space outside nucleus

atom:

smallest particle of an element that retains the properties of said element

are subatomic particles (below atomic) considered a part of matter

no, they are subdivisions of the atom

do electrons have a mass?

no, negligible

how are electrons arranged?

in energy levels around the nucleus

what are electrons responsible for affecting?

atomic volume (volume of one mol of element at room temperature)

do protons have a mass?

yes

what do protons determine, and how?

• physical properties of element

  • since # of protons affect the atomic number of an element, changing it affects the properties

do neutrons have a mass?

yes

do neutrons affect the physical properties of an element

no, proton’s job

isotope

variations of an element affected by a change in atomic mass (or the # of neutrons, since # of protons are the same)

what are the relative masses of all subatomic particles?

• electron: 0

• proton, neutron: 1

how to represent the structure of an atom w the nuclear symbol?

Z = atomic number

A = mass number (protons + neutrons)

X = element symbol

write the isotope aluminum-27 in two ways.

• aluminum-27

• superscript 27Al

average atomic mass (amu)

weighted average of masses of each isotope of an element

what does the mass of 1 proton or neutron equate to?

1/12th of the mass of a carbon-12 atom

how do you calculate the average atomic mass of an element?

[mass (#) * abundance] + [mass (#) * abundance] + however many isotopes there are

how are emission spectrums produced?

atoms release light energy (via photons of light) when electrons in excited states return to lower energy levels

electromagnetic radiation

photons that travel in waves at the speed of light in a vacuum

wavelength

peak to peak (horizontal)

frequency

top point to bottom point of wavelength (vertical)

how are the wavelength and frequency of light related?

• INVERSE relationship

  • longer wavelength, shorter frequency, and vice versa

what is the formula for measuring relation between wavelength and frequency?

speed of light = wavelength * frequency

shortest to longest wavelength from infrared, visible, UV

UV, visible light, infrared light

continuous spectra

all POSSIBLE wavelengths of light are present

• sunlight is an example, since it shows all colors of the rainbow (all spectra)

emission spectrum

series of lines on a dark background, that show the color

how do you create an emission spectrum?

absorption spectrum

series of dark lines in a continuous spectrum

how to create absorption spectrum

ground state

electrons at lowest possible energy level

excited state

electrons ABSORB energy to move into higher energy levels

as electrons move higher and lower between energy level, what happens to the energy

• move up = absorbs

• move down = releases

photon

quantum of energy

what is the relationship between energy and frequency

DIRECTLY proportional

• more energy, higher frequency, and vice versa

formula for energy + frequency relationship

energy = plank’s constant * frequency

formula for relationship between energy level and total energy in electron

energy = rydberg’s constant * (1/energy level)

what is the relationship between electrons and its energy level

DIRECT relation

• more energy, more energy levels