Choose the best answer to given of the following. Explain your reasoning with one or more complete sentence.
Why is a sunflower yellow?
(a) It emits yellow light.
(b) It absorbs yellow light.
(c) It reflects yellow light.

Energy Level Transitions.
The following labeled transitions represent an electron moving between energy levels in hydrogen. Answer each of the following questions and explain your answers.
a. Which transition could represent an atom that absorbs a photon with 10.2 eV of energy?
b. Which transition could represent an atom that emits a photon with 10.2 eV of energy?
c. Which transition represents an electron that is breaking free of the atom?
d. Which transition, as shown, is not possible?
e. Would transition A represent emission or absorption of light? How would the wavelength of the emitted or absorbed photon compare to that of the photon involved in transition C? Explain.

The atomic number of gold (Au) is 79, and the atom has a mass number of 197. How many neutrons are present in the atom of gold?

A. 79

B. 118

C. 197

D. 276

Choose the best answer to given of the following. Explain your reasoning with one or more complete sentence.
Ionization is the process by which
(a) electrons escape from atoms.
(b) liquid material enters the gas phase.
(c) molecules break apart into individual atoms.

Atomic Terminology Practice II.
a. What are the atomic number and atomic mass number of a fluorine atom with $9$ protons and 10 neutrons? If we could add a proton to this fluorine nucleus, would the result still be fluorine? What if we added a neutron to the fluorine nucleus? Explain.
b. The most common isotope of gold has atomic number $79$ and atomic mass number $197$. How many protons and neutrons does the gold nucleus contain? If the isotope is electrically neutral, how many electrons does it have? If it is triply ionized, how many electrons does it have?
c. Uranium has atomic number $92$. Its most common isotope is $^{238}U$, but the form used in nuclear bombs and nuclear power plants is $^{235}U$. How many neutrons are in each of these two isotopes of uranium?

Atomic Terminology Practice $I$. a. The most common form of iron has $26$ protons and $30$ neutrons. State its atomic number, atomic mass number,and number of electrons (if it is neutral).
b. Consider the following three atoms: Atom 1 has $7$ protons and $8$ neutrons; atom $2$ has $8$ protons and $7$ neutrons; atom $3$ has $8$ protons and $8$ neutrons. Which two are isotopes of the same element?
c. Oxygen has atomic number $8$. How many times must an oxygen atom be ionized to create an $0^{+5}$ion? How many electrons are in an $0^{+5}$ ion?

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
If a distant galaxy has a substantial redshift (as viewed from Earth), then anyone living in that galaxy would see a substantial redshift in a spectrum of the Milky Way Galaxy.

LEDs are considered an even better alternative to CFLs to replace incandescent bulbs. Compare CFLs with LEDs. Are LEDs a better alternative? Be sure to consider environmental, health, and economic factors. Write a brief report to communicate your opinion

Do atoms in excited states emit radiation randomly, at any wavelength? Why? What does it mean to say that the hydrogen atom has only certain discrete energy levels available? How do we know this? Why was the quantization of energy levels surprising to scientists when it was first discovered?

LEDs are considered an even better alternative to CFLs to replace incandescent bulbs. Compare CFLs with LEDs. Are LEDs a better alternative? Be sure to consider environmental, health, and economic factors. Write a brief report to communicate your opinion

The AU is defined as the average distance between Earth and the Sun, not the distance between Earth and the Sun. Why does this need to be the case?

What makes the visible spectrum of light visible?

What kind of spectrum does a neon sign produce?

A light bulb that glows when a filament inside it gets hot is $a(n)$ a. vapor light. b. fluorescent light. c. incandescent light. d. neon light.