Chemistry: Spectroscopy

When an excited electron in an atom moves to the ground state, the electron (a) emits energy as at moves to a lower energy state, (b) absorbs energy as it moves to a lower energy state, (c) emits energy as it moves to a higher energy state, (d) absorbs energy as it moves to a higher energy state.

(a) emits energy as it moves to a lower energy state

Problem: How can the Bright Line Spectrum of each unknown element be used to identify the element?

Each element has its own unique bright line spectra, like a finger print.

Why do the different substances show different spectral lines?

Electrons are located in specific energy levels, and therefore, only certain energy changes are possible that are unique to each element and create unique bright line spectra.

What happens to an electron when energy is added?

The electron absorbs energy and jumps to a higher energy level.

Why are the frequencies (color) for a specific element always the same?

The electrons of the atoms of an element are located in specific energy levels, and only certain energy changes are possible when the electrons move back to the ground state from higher energy levels. The mixture of specific spectral lines creates the overall color specific to that element.

Why do you think the chemicals have to be heated in the flame before the colored light is emitted?

The heat provides the energy for the electrons to become "excited" and move to higher energy levels before they fall back down to a ground state and release light.

How do firework manufacturers get specific colors?

They mix specific elements that when heated, emit the colors they desire depending upon their unique bright line spectra.

Why did each gas only show one color when it is viewed without the spectroscope?

Without the spectroscope, the light emitted is not divided into its various wavelengths and the one color seen is a mixture of all of the spectral lines.

Is the spectrum for the incandescent light a continuous spectrum or a bright line spectrum? Why?

a continuous spectrum When the white light is passed through a prism, all the wavelengths of light (all colors of the rainbow) are seen.

What is light?

a form of energy that travels in waves

What is released when an electron loses energy?

a photon, or particle of light, in the visible spectrum

What do the neon lights of Broadway, fireworks, fireflies, glow sticks and Bohr all have in common?

all emit energy in form of light at different wavelengths/colors

Define excited state.

an electron absorbs energy and "jumps" to a higher energy level the electron is not as stable at the higher level and falls back to the ground state, emitting light energy

Define emission spectra.

colored lines produced as electron "falls" back to its original energy level, or ground state after "jumping" to a higher one, it releases energy in the form of light that travels in wavelengths, or colored lines.

What is the difference between the continuous line spectra/spectrum and the bright line spectra/spectrum?

continuous line spectra/spectrum: includes light with ALL the wavelengths in the visible spectrum that is seen as a rainbow (ROYGBIV) bright line spectra/spectrum: emits ONLY CERTAIN wavelengths of light in the continuous line spectra; the bright line spectra is unique to each element

What is the formula for E?

hc/lamda h=Plank's constant c=speed of light lamda = wavelength

The further from the nucleus the energy level is, the ________ the energy associated with the energy level.

higher

What is the relationship between energy and the wavelength of light?

indirect as energy increases, wavelength decreases

What is the ground state of an electron?

its original or lowest possible energy level

Define ground state.

lowest energy level of electrons

All light travels at the same ________ but its __________ and ________ are different.

speed wavelengths (distance between peak to peak or trough to trough) energy

What is meant when we say that energy levels for electrons are QUANTIZED?

that electrons only exist in certain, specific energy levels

What is the electromagnetic spectrum?

the entire range of wavelengths or frequencies of electromagnetic radiation

What is spectroscopy?

the study of how matter interacts with or produces light

What determines the frequency (color) of photons?

their different energies (and wavelengths which are indirectly related to energy)

What is the purpose of a spectroscope?

to separate the light emitted into its different wavelengths (colors) so the bright line spectra of each element can be seen

The bright line spectra is ___________ to a given element and can be used to ___________ it like a fingerprint.

unique identify

When does an electron become "excited"?

when it absorbs energy and then jumps to a higher energy level than it should be