Chemistry 3rd Nine Weeks Test Review

What information does a molecular formula provide?

• the number and kind of atoms that are bonded by the transfer of electrons

• the simplest whole-number ratio of atoms that are bonded by the transfer of electrons

• information about a molecule’s structure

• the number and kind of atoms present in a molecule

How do atoms achieve noble-gas electron configurations in single covalent bonds?

• One atom completely loses two electrons to the other atom in the bond.

• Two atoms share two pairs of electrons.

• Two atoms share two electrons.

• Two atoms share one electron.

Why do atoms share electrons in covalent bonds?

• to become ions and attract each other

• to attain a noble-gas electron configuration

• to become more polar

• to increase their atomic numbers

Which elements only form diatomic molecules joined by a single covalent bond?

• hydrogen only

• halogens and members of the oxygen group only

• hydrogen and the halogens only

• hydrogen and the noble gases only

Which of the following diatomic molecules is joined by a double covalent bond?

• O2

• Cl2

• N2

• He2

Once formed, how are coordinate covalent bonds different from other covalent bonds?

• They are stronger.

• They are more ionic in character.

• They are weaker.

• There is no difference.

How many valid electron dot formulas—having the same number of electron pairs for a molecule or ion—can be written when a resonance structure occurs?

• 0

• 1 only

• 2 only

• 2 or more

The side-by-side overlap of p orbitals produces what kind of bond?

• alpha bond

• beta bond

• pi bond

• sigma bond

Which of the following bond types is normally the weakest?

• sigma bond formed by the overlap of two s orbitals

• sigma bond formed by the overlap of two p orbitals

• sigma bond formed by the overlap of one s and one p orbital

• pi bond formed by the overlap of two p orbitals

Experimental evidence suggests that the H—C—H bond angles in ethene, C₂H₄, are ____.