Preap Chemistry

The molecule with the largest dipole moment

• CO2

• H20

• CH4

• C2H4

A particle-level diagram of a metallic element is shown above. Typically, metals are both malleable and ductile. The best explanation for these properties is that the electrons involved in bonding among metal atoms are

• unequally shared and form nondirectional bonds

• unequally shared and form highly directional bonds

• equally shared and form nondirectional bonds

• equally shared and form highly directional bonds

Tags

NGSS.HS-PS1-3

The melting point of MgO is higher than that of NaF. Explanations for this observation include which of the following?

I. Mg2+ is more positively charged than Na+.

II. O2- is more negatively charged than F-.

III. The O2- ion is smaller than the F- ion.

• II only

• I and II only

• I and III only

• II and III only

Tags

NGSS.HS-PS1-3

the energy required to dissociate an ionic solid into gaseous ions (lattice energy) for the compounds NaF and MgF2 is shown in the table above. On the basis of Coulomb's law, which of the following best helps to explain the large difference between the lattice energies of NaF and MgF2 ?

• The solubility of MgF2 is less than that of NaF.

• The electronegativity of Mg is greater than that of Na.

• The mass of the Mg cation is greater than that of the Na cation.

• The charge of the Mg cation is larger than that of the Na cation.

Tags

NGSS.HS-PS2-4

Which of the following has a zero dipole moment?

• HCN

• NH3

• SO2

• NO2

• PF5

which of the following lewis dot diagrams describe the molecules that are the most polar?

• ClF

• BrF

• CS2

• BF3

Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound?

• It has the formula XZ2.

• It does not dissolve in water.

• It contains ionic bonds.

• It contains covalent bonds.

Tags

NGSS.HS-PS1-3

Has a trigonal-pyramidal molecular geometry

• H2O

• NH3

• BH3

• CH4

• SiH4

Which of the following scientific claims about the bond in the molecular compound HF is most likely to be true?

• There is a partial negative charge on the H atom.

• Electrons are shared equally between the H and F atoms.

• The bond is extremely weak.

• The bond is highly polar.

Tags

NGSS.HS-PS1-1

The lattice energy of a salt is related to the energy required to separate the ions. For which of the following pairs of ions is the energy that is required to separate the ions largest? (Assume that the distance between the ions in each pair is equal to the sum of the ionic radii.)

• NaCl

• CaBr

• MgO

• CaO

Tags

NGSS.HS-PS2-4