In what way does the need for iodine or iron in your diet differ from your need for calcium or phosphorus?

The reactivity of an atom arises from

a. The average distance of the outermost electron shell from the nucleus.

b. The existence of unpaired electrons in the valence shell.

c. The sum of the potential energies of all the electron shells.

d. The potential energy of the valence shell.

Changing the _________ would change it into an atom of a different element.

a. Number of electrons surrounding the nucleus of an atom

b. Number of protons in the nucleus of an atom

c. Electrical charge of an atom

d. Number of neutrons in the nucleus of an atom

Add labels to the figure that follows, which illustrates the subatomic particles associated with a carbon atom.

Electrons ________.

a. Are negatively charged.

b. Along with neutrons make up the nucleus.

c. Are attracted to the negatively charged nucleus.

d. Are not involved in ionic bonds.

e. All of the above are true.

Draw Lewis dot structures for each hypothetical molecule shown below, using the correct number of valence electrons for each atom. Determine which molecule makes sense because each atom has a complete valence shell, and each bond has the correct number of electrons. Explain what makes the other molecule nonsensical, considering the number of bonds each type of atom can make.

Use carbon-12, the most common isotope of carbon, to define these terms: atomic number, mass number, valence. Which of these numbers is most related to the chemical behavior of an atom? Explain.