Choose the statements that are true about bonds

a if atoms have a big electronegativity difference they for an ionic bond
b in ionic bonds electrons are shared between atoms
c in covalent bonding electrons are shared between atoms
d if atoms have a big electronegativity difference they form a covalent bond

Which object is most likely represented by a dot?

Some material consisting of a collection of microscopic objects is kept at a high temperature. a photon detector capable of detecting photon energies from infrared through ultraviolet observes photons emitted with energies of 0.3 ev, 0.5 ev, 0.8 ev, 2.0ev, 2.5ev, and 2.8ev. these are the only photon energies observed. (a) draw and label a possible energy-level diagram for one of the microscopic objects, which has four bound states. on the diagram, indicate the transitions corresponding to the emitted photons. explain briefly. (b) would a spring–mass model be a good model for these microscopic objects? why or why not? (c) the material is now cooled down to a very low temperature, and the photon detector stops detecting photon emissions. next, a beam of light with a continuous range of energies from infrared through ultraviolet shines on the material, and the photon detector observes the beam of light after it passes through the material. what photon energies in this beam of light are observed to be significantly reduced in intensity (“dark absorption lines”)? explain briefly.

If we relied solely on the nonrenewable resources found in the u.s., which one would we run out of first at current usage levels? a. natural gas b. oil c. uranium d. coal