Exam 2: The Chemical Context of Life

Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?

Refer to the following figure to answer the questions below. -Based on electron configuration, which of the elements in the figure would exhibit a chemical behavior most like that of oxygen?

Refer to the following figure to answer the questions below. -What causes the shape of the molecule shown?

Which of the following is broken when water evaporates?

In the term trace element, the adjective trace means that

How many electron pairs are shared between carbon atoms in a molecule that has the formula C₂H₄?

Which of the following is the best description of an atom's physical structure?

A neutral atom has two, eight, eight electrons in its first, second, and third energy levels. This information ________.

Refer to the following figure (first three rows of the periodic table) to answer the questions below. -What element does not prefer to react with other elements?

The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?

Which of the following statements correctly describes any chemical reaction that has reached equilibrium?

Refer to the following figure to answer the questions below. -How many electrons are present in a Phosphorus 3+ atom?

The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.

Which one of the atoms shown would be most likely to form an anion with a charge of -1?

What is the difference between covalent bonds and ionic bonds?

Refer to the following figure (first three rows of the periodic table) to answer the questions below. -Which pair of elements would likely have similar valency and thus similar chemical behavior?

A covalent chemical bond is one in which ________.

Refer to the following figure to answer the questions below. -An atom has four electrons in its valence shell. What types of covalent bonds is it capable of forming?

Refer to the following figure to answer the questions below. -What results from the chemical reaction in the illustration? The reactants have no charge.

Refer to the following figure to answer the questions below. -If an atom has a charge of +1, which of the following must be true?