2.5 Spectroscopy

The table shows the ranges of visible light wavelengths.

An atom absorbs energy corresponding to the wavelength of red light. What would you expect to see on the atom's absorption spectrum?

• A red line around 425 nm

• A red line around 700 nm

• A black line around 700 nm

• A black line around 425 nm

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3

Why can emission and absorption spectra be used to identify elements?

• each element has a unique emission and absorption spectra.

• each element is associated with lightwaves of only one wavelength and emits just one color.

• each element has its own emission spectrum, though its absorption spectrum is shared by many elements.

• each element has its own absorption spectrum, though its emission spectrum is shared by many elements.

An atom emits a photon of light. What could cause this to happen?

• an excited atom moves to a higher energy level.

• an atom gains energy as it absorbs an incoming electron.

• an atom releases energy by rearranging its electron levels

• an electron releases energy as it moves to a lower energy level.

Neon lighting is one application using concepts from emission spectroscopy. Which of the following best describes how the emission process works in neon lighting?

• Ultraviolet light excites the neon gas to produce emitted white light.

• Energy excites the neon gas to an excited state. The relaxation to ground state causes light to be emitted.

• Neon gas reacts with oxygen in the air, which causes the emission of light.

• none of the above.

Mercury atoms emit photons of light at 436 nm and 546 nm. Based on this, what can you conclude about mercury?

• Its emission spectrum has an indigo line and green line

• Its emission spectrum has a yellow line and a red line

• Its absorption spectrum has an indigo line and a green line

• Its absorption spectrum has a yellow line and a red line

Tags

NGSS.HS-PS4-3

The following photons were produced when excited electrons fell back to their original energy level. Order the photons from the least energy emitted to the most energy emitted.

• orange, yellow, green, violet

• violet, green, yellow, orange

• green, yellow, orange, violet

• yellow, violet, green, red

The absorption spectrum of helium has a black vertical line at a wavelength of 502 nm. What can you conclude about atoms of helium?

• They emit photons with a wavelength of 502 nm

• They do not emit photons with a wavelength of 502 nm

• They emit photons with a wavelength that is slightly above 502 nm

• They emit photons with a wavelength that is slightly below 502 nm

When energy is added to an atom, which of the following events is most likely to occur?

• all of the atom's electrons are emitted as electric energy

• all of the atom's electrons are moved to different energy levels

• some of the atom's electrons move to lower energy levels

• some of the atom's electrons move to higher energy levels

What are emission spectra?

• the wavelengths of light that are stored in electrons from an element when it is exposed to light

• the wavelengths of light that are emitted from an element when it is exposed to light

• the wavelengths of light that are absorbed by an element when it is exposed to light

• the wavelengths of light that are neither emitted or absorbed