Introduction to Chemistry Chapter 3 - Review Questions

1. If water vapor is invisible why can we see clouds?
2. Compare and contrast atom and element.
3. High energy light photons in the ultraviolet range can strike some substances causing the electrons in those substances to jump to a higher energy shell. Make a before and after sketch of this shell jump using the Bohr atomic structure diagram of oxygen. When the excited electron drops back to the original energy level it will emit a light photon but at a visible light wavelength. This effect is used in black light posters. Make a third Bohr diagram sketch showing the atom returning to its 'resting' state and emitting a photon.

4. The following compounds have ionic bonds: NaF, KCl, CaBr₂. Using your periodic table, make a generalized statement about which elements will likely form ionic compounds?
5. The following compounds have covalent bonds: CO₂, H₂O, ICl. Using your periodic table, make a generalized statement about which elements will likely form covalent compounds?
6. Explain why all isotopes aren't radioactive.
7. Why do we say water has single covalent bonds, CO₂ has double and N₂ has triple covalent bonds?
8. Explain why the photosynthesis reaction is endothermic. 6 H₂O + 6 CO₂ + sunlight C₆H₁₂O₆ + 6 O₂
9. How can the polar nature of water molecules explain surface tension seen in water?
10. Compare and contrast acids and bases.