Physics 32 Questions

The massive alpha particles blast through the majority of the space in the gold that is occupied by low mass electrons.

The mass of the atom is concentrated in a positively charged core. The high-density core of an atom is extremely small compared to the size of the atom. The mass of an atom is concentrated in a high-density core.

It was a fluid that could exist in excess, called positive, or in deficiency, called negative.

A beam of electrons

The mass-to-charge ratio of particles in the beam. JJ Thomson measured the beam's deflection in electric and magnetic fields. Reasoned that amount of beam's deflection depended on mass of particles and their electric charge. Greater particle mass = greater inertia, less deflection. Greater particle charge = greater force, greater deflection. Greater speed = less deflection.

For discovering the electron, established with careful measurements of the deflection of the beam, calculating the mass-to-charge ratio of the cathode ray particle.

The charge and the mass of the electron. The charge on each drop was always some multiple of a single very small value, which he proposed to be the fundamental unit of charge carried by each e-. Then calculated the mass to be about 1/2000 the mass of an H atom.

He discovered a mathematical formula that described the pattern of wavelengths in the line spectra of hydrogen. This could be used to predict other lines of H not let measured.

They discovered that the spectral lines of any element include lines with frequencies that are the sums and differences of the frequencies of other lines.

The energy difference between two electron orbits would equal the energy of an emitted photon.

No. There can be only one! The energy and frequency (color) of that photon depends on the size of the jump, though.

The energy difference between orbits is equal to the sum of the energies of photons emitted by an electron going from one orbit to the other.

Electron orbits can only hold an integer number of wavelengths of the electron standing wave. Like a paper clip chain necklace circumference is equal to a multiple of the single paper clip length.

1, 2, n

Electrons behave like a standing wave, not like a charged particle in an orbit that would lose energy and emit radiation. The circumference of the smallest orbit can be no smaller than one wavelength; no fraction is possible in a circular or elliptical standing wave. As long as the e- carries the momentum necessary for wave behavior, atoms don't shrink in on themselves.

It can be used to calculate the probability of the result of an experiment. Ψ represents the possibilities that can occur in a system. Possible position and PROBABLE position (at a particular time) are not the same! Calculate the probable position by multiplying the wave function by itself (|Ψ|)^2.

The probability density function is the wave function times itself and gives the probability per unit volume of an experimental outcome.

The average distance of the cloud from the nucleus is close to that of the radius of the Bohr orbit. An individual electron may, at various times, be detected anywhere in this probability cloud; it even has an extremely small but finite probability of momentarily existing inside the nucleus.

The experimental predictions of a new theory have to match the experimentally verified predictions of the old theory in the domains where the old theory works.

Schrödinger's equation should be valid but useless. "Bohr was quick to stress that his model was...not to be taken literally... like planets about the sun"

A continuous spectrum, because the electron would be able to exist in any energy state. The fact that we see a line spectrum shows that the electron can only exist in certain, discrete energy states.

Because the quantum nature of matter and energy is only noticeable on subatomic scales. In everyday situations the laws of quantum mechanics "average out" and are indistinguishable from classical laws.

The values of radii of Bohr's orbits are discrete. The circumference of the innermost orbit is equal to one wavelength. No fractions of a wavelength!

The electron is though of not as a particle located at some point in the atom but as if its mass and charge were spread out into a standing wave surrounding the atomic nucleus -- with an integral (discrete) number of wavelengths fitting evenly into the circumferences of the orbits. Multiples of one wavelength! No fractions! (fig. 32.10)

The values of radii of Bohr's orbits are discrete. The circumference of the innermost orbit is equal to one wavelength; thus each electron orbit is equal to a multiple of the wavelength. NO half or fraction wavelengths!

Ψ (matter wave amplitude) represents the possibilities that can occur in a system. Possible position and PROBABLE position (at a particular time) are not the same! Calculate the probable position by multiplying the wave function by itself (|Ψ|)^2. This equation (Probability Density Function) gives the probability per unit volume of an experimental outcome.