gold foil experiment (nuclear model), bohr model and electromagnetic spectrum

5/3/25 + 11/2/25

summary of gold foil experiment

• ernest rutherford

• fired alpha particles (tiny and charged particles smaller than atom) at gold foil

• found that 1 - majority of alpha α particles shoot straight through

• 2- a small fraction of alpha α particles found at small angles

• 3- tiny fraction of alpha α particles detected in front of the foil

conclusions of gold foil experiment

• most of atom is empty space

• positively charged centers consist of majority of mass

• mass and charged are not uniformly distributed

• nuclear model of atom: positively charged nucleus with electrons orbiting nucleus

electrostatic force

Force of attraction and repulsion between protons and electrons

principal quantum number

• orbits outside of nucleus

• n = 1, 2, 3… infinity

• electron is never between any two states

when electron goes closer/farther from nucleus

• gives off a quantum of energy exactly equal to the difference between the two states when going from excited to ground

• when going away from nucleus, ground to excited or further, absorb a quantum of energy exactly equal to the difference between the two states when going from excited to ground

what determines the attraction of electrons and protons

the attraction between electrons and protons depends on the number of protons

frequency is proportional to…

• frequency is inversely proportional to wavelength

• high frequency, short wavelength

• low frequency, long wavelength

incandescent light is a

continuous spectrum

are orbits of electron dynamic or static?

• dynamic

• change according to forces/function of forces

• different forces, different energy

line spectra and identifying elements

• all elements give off a different spectra

• spectras can be used to identify elements

• the spectra depends on the energy in the element which depends on the force of attraction in the atom

• electron is attracted to nucleus

• the nucleus charge/number of protons determines the force of attraction

• Every element has a different number of protons therefore different levels of attraction therefore different energy levels therefore different line spectrums