Bio 2 Chapter 2 Guided Reading

Any orbital can hold only how many electrons?

2

Because water is ____________, it is able to dissolve many of life's important substances.

A solvent

Which of the following is a unique property of water?

All of the above

As the pH increases the [H1] ____________, and as the pH decreases the [H1] ____________.

As the pH increases the [H+] decreases, and as the pH decreases the [H+] increases.

Complete the diagram illustrating ionic bonds. Atom X gives one electron to each atom Y. What are the ions that form as a result? Put the charges under each atom.

Atom y is negatively charged, atom x is positively charged, and atom y is negatively charged.

Complete the following table by filling each line with the correct value.

Carbon-12: 6, 12, 6, 6, 6 Hydrogen-1: 1, 1, 1, 0, 1 Phosphorous-31: 15, 31, 15, 16, 15 Fluorine-19: 9, 19, 9, 10, 9 Carbon-13: 6, 13, 6, 7, 6

____________ are changes in matter that result in new substances being made by breaking existing chemical bonds, rearranging the atoms into new substances, and forming new chemical bonds.

Chemical reactions

What are the three ways in which atoms can interact with one another with respect to their electrons?

Double, single, or nonpolar covalent bonds

Use the two examples that you provided in question 4 to describe how these trace elements have been introduced into our diets and habits.

Iron is introduced to the diet through meat, fruits, and vegetables. Iodine is introduced to the diet through salt, meat, eggs, and bread.

Which of the following are atoms of an element that vary in the number of neutrons?

Isotopes are atoms that vary in the number of neutrons

How much more [H1] does lemon juice have compared to pure water? Use Figure 2.14 on page 28 of your textbook.

Lemon juice has 5 more [H+] than pure water.

Many students have difficulty understanding how giving up an electron to another atom fills the valence of the atom that gave up the electron. It seems counterintuitive to them that losing an electron actually fills their valence. Imagine you are a teacher trying to explain this particu- lar concept to a student. Briefly describe what you would say.

Losing valence electrons actually helps the element become stable because without the extra electrons in its outermost shell, makes the element have the same amount of electrons as the noble gas that came before it on the periodic table.

Neapolitan ice cream is vanilla, chocolate, and strawberry combined in a 1:1:1 ratio. Briefly explain how Neapolitan ice cream is a good analogy that helps students understand the relationship between compounds and elements.

Neapolitan ice cream helps students to understand the relationships between compounds and elements because the individual flavors represent the elements in the compound and Neapolitan is the compound made up of the flavors.

An atom of carbon has six protons. What if you change the number of protons to seven? Is it still carbon? Briefly explain your answer.

No because a carbon atom has to have six protons.

Oils are nonpolar substances (molecules formed by nonpolar covalent bonds) that do not in- teract with water. Propose an explanation for why oils are not attracted to water, whereas a substance like NaCl (table salt) is attracted to H2O.

Oils are not attracted to water because they are nonpolar. However, NaCl is attracted to water because it is polar. Polar molecules are attracted to polar molecules.

Electrons are found in ____________ that surround the nucleus at distinct distances.

Orbitals

Complete the Venn diagram that compares polar covalent bonds to nonpolar covalent bonds.

Polar covalent bonds Contains water Both Involve sharing electrons Nonpolar covalent bonds Molecules of one element Each atom has the same electronegativity

Radioactive isotopes are commonly referred to as "biological spies." Briefly explain why this is an accurate description. Your explanation should include two specific examples of radioactive isotopes being used as "spies."

Radioisotopes are considered biological spies because they can act as tracers.

You are a research scientist working for an oil exploration company. A molecule is isolated from a sample taken from a new test well the company is drilling. Initial tests indicate that the molecule is nonpolar. What elements are likely to make up the molecule? Briefly explain your answer.

The element is likely to be made of elements that have the same electronegativity because the molecule is nonpolar.

In the following chemical equation, identify the products and reactants and indicate whether or not the equation is balanced. If not, balance the chemical equation.

The equation is balanced

Students tend to think that, because trace elements are required in tiny quantities, they are not important. List two trace elements that humans require and briefly explain why those two trace elements are important.

Trace elements are important because without iron the body cannot transport oxygen and an iodine deficiency prevents the production of thyroid hormones.

True or false: A radioactive isotope is unstable, which means it gives off energy and particles. If false, make it a correct statement.

True

True or false: An ionic bond is based on the transfer of electrons between two atoms. If false, make it a correct statement.

True

True or false: Ocean acidification is when CO2 dissolves in ocean water and lowers the pH. If false, make it a correct statement.

True

The search for life on other planets hinges on finding ____________.

Water

Fill in the following diagram at right, which illustrates the relationship between compounds and elements. Provide an example of each in the space below.

a. Elements b. Compounds

Match the following terms with their definitions: ionic bond, covalent bond, polar covalent bond, nonpolar covalent bond, and hydrogen bond.

a. Hydrogen bond b. Covalent bond c. d. Ionic bond e.

Match the following terms with their correct definitions: matter, trace element, emergent properties, element, and compound.

a. Trace elements are required by humans in small quantities b. An atom cannot be chemically broken down into a simpler substance c. Anything that takes up space and mass is matter. d. Compounds are substances that have two or more elements in a fixed ratio.

Match the following terms with their correct definitions: adhesion, temperature, surface tension, evaporative cooling, and thermal energy.

a. evaporative cooling b. surface temperature c. temperature d. adhesion e. thermal energy