Chapter Three Tro Chemistry

What is the Schrodinger equation? What is wave function? How is wave function related to an orbital?

Wave function is a mathematical function that describes the wave-like nature of the electron. A plot of the wave function squared represents an orbital, a probability density distribution map of the electron

What determines the color of light? Describe the difference between red and blue light.

The different colors in visible light corresponds to different wavelengths (Or Frequencies). Red light appears on a wavelength of about 750 nanometers (the longest wavelength). Blue light appears at about 450 nanometers, just before violet (the shortest at 300 nm).

What is a photon? How is the energy of a photon related to its wavelength? Its frequency?

A packet of light is a called a photon, or a quantum of light. The energy of a photon is inversely proportional to its wavelength. The energy of a photon is directly proportional to its frequency.

What determines the color of a colored object? Explain why grass appears green.

A substance that absorbs some colors while reflecting others, appears colored. For example grass appears green because it reflects predominantly green light while absorbing most other colors, our eyes only see reflected light so the grass will appear green.

What is an emission spectrum? How does an emission spectrum of a gas in a discharge tube differ from a white light spectrum?

An emission spectrum is the range of wavelengths emitted by a particular element; used to identify an element. The white light spectrum is continuous, meaning that there are no sudden interruptions, all the wavelengths lights are shown. Within the discharge tube, it goes from total black to only the colors the colors needed at specific points.

Define the frequency of electromagnetic radiation. How is frequency related to wavelength?

Frequency is the number of cycles (or wave crests) that pass through a stationary point in a given period of time. Frequency is inversely proportional to wavelength, the father apart the crests, the fewer will pass a fixed location per unit time.

Explain Heisenberg's uncertainty principle. What paradox is at least partially solved by the uncertainty principle?

Heisenberg's uncertainty principle states that the product or deltaX and Mdeltav must be greater than or equal to a finite number (h/4pie). AKA. the more accurately you know the position of an electron, the less accurately you can know its velocity and vice versa. This solves the paradox that we don't know if something can be both a particle and a wave.

Describe the Bohr model for the atom. How did the Bohr model account for the emission spectra of atoms?

In this model, electrons travel around the nucleus in circular orbits (Analogous to those of the planets around the sun). However, Bohr's orbits exist only at specific, fixed distances from the nucleus and because of this the energy of each orbit is also fixed, or quantized. It may exist in two states but it can only ever be observed in one state or the other, because of this the emission spectrum of the atom consists of discrete lines because the stationary states exist only at specific, fixed energies.

What is light? How fast does it travel in a vacuum?

Light is electromagnetic radiation, an energy embodied in oscillating electric and magnetic fields. In a vacuum these waves move at a constant speed of 3.00 x 10^8 m/s (186,000 mi/s)

What are the possible values of the angular momentum quantum number L? What does the angular momentum quantum number determine?

Possible values of AMQN (l) are 0,1,2...(n-1). In other words for a given value of n, l can be any integer (including 0) up to n-1. This is an integer that determines the shape of the orbital.

What are the possible values of the magnetic quantum number m? What does the magnetic quantum number determine?

Possible values of MQN (ml) are the integer values (including 0) ranging from -L to +L. For example if L=0, then the only possible value of ml is 0 or if L-1 then ml can be -1,0. It is an integer that specifies the orientation of the orbital.

What are the possible values of the principal quantum number n? What does the principal quantum number determine?

Possible values of the PQN (n) are 1,2,3 and so on. It is an integer that determines the overall size and energy of an orbital.

What is quantum-mechanical orbital?

The electrons position is described in terms of an orbital, a probability distribution map showing where the electron is likely to be found.

Define wavelength and amplitude of a wave.

The wavelength of the wave is the distance between adjacent crests (or any two analogous points) and is measured in unites such as meters, micrometers, or nanometers. Wavelength determines the light's color.The amplitude of the wave is the vertical height of a crest (Or depth of a trough). It determines the light's intensity or brightness (Bigger amplitude, bigger intensity).