Describe how light is emitted from an atom. a) as protons absorb energy they travel from the nucleus through the atom emitting light along the way. b) the light is emitted when energy from sunlight is absorbed by the atom to excite a neutron into a higher level. c) when the nucleus absorbs sunlight, photons are energized and move to a higher energy level and are then released. d) light is emitted from an atom as an electron falls from an excited state to the ground state releasing a photon.

Answer is: D)Light is emitted from an atom as an electron falls from an excited state to the ground state releasing a photon.

Electrons can jump from one energy level to another, absorbing or emitting electromagnetic radiation with a frequency ν (energy difference of the levels).

When electron jump from higher to lower energy level (shell), it emitting (releasing) energy.

For example, when the electron changes from n=4 (fouth shell) to n=2 (second shell), the photons are emitted.

Albert Einstein (1879-1955) proposed that a beam of light is a collection of discrete wave packets (photons) with energy hν, where h is Planck constant and ν is frequency.

The photons have a characteristic energy proportional to the frequency of the light.

Minimum frequency or the threshold frequency is energy below which no photoelectrons are emitted.  

Above the minimum frequency, energy depends on the frequency of the light, not on the intensity of the light.

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nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.