Use VSEPR theory to predict the shape of each molecule:

a. $\text{GaH}_{3}$

b. $\text{OF}_{2}$

c. HCN

d. $\text{CCl}_{4}$

e. $\text{SeO}_{2}$

Compare the electron-dot formulas of $\mathrm{CH}_4$ and $\mathrm{H}_2 \mathrm{O}$. Why do these molecules have similar bond angles but different names for their shapes?

Which of the following is the correct name for FePO3 ?

A. iron(III) phosphate, ferric phosphate

B. iron(II) phosphate, ferrous phosphate

C. iron(III) phosphite, ferric phosphite

D. iron(II) phosphite, ferrous phosphite

E. iron phosphorus trioxide

Compare the electron-dot formulas of $\text{BF}_{3}$ and $\text{NF}_{3}$. Why do these molecules have different shapes?

In a molecule of H_{2}, the four electron groups around the sulfur atom are arranged in a tetrahedral geometry. However, the shape of the molecule is called bent. Why does the shape of the molecule have a different name from the name of the electron group geometry?

In the molecule $\text{PCl}_{3}$, the four electron groups around the phosphorus atom are arranged in a tetrahedral geometry. However, the shape of the molecule is called trigonal pyramidal. Why does the shape of the molecule have a different name from the name of the electron group geometry?

100 g of a clear liquid is evaporated and a few grams of white crystals remain. The original liquid was a (1) heterogeneous compound, (2) heterogeneous mixture, (3) homogeneous compound, (4) homogeneous mixture.

Which of the following is true of a compound but not a mixture? (1) Acompound contains more than one element. (2) All the nuclei in a compound contain the same number of protons. (3) Acompound may be heterogeneous. (4) The composition of a compound does not vary.

Predict the shape of a molecule with each of the following:

a. Four bonded atoms

b. Two bonded atoms and two lone pairs

Predict the shape of a molecule with each of the following:

a. Two bonded atoms and no lone pairs

b. Three bonded atoms and one lone pair

The atomic number corresponds to the number of ________ in a specific element, while the atomic weight corresponds to the number of ________ in a specific element.

a. protons; protons and neutrons

b. protons and neutrons; neutrons

c. protons; neutrons

d. neutrons; protons

Draw resonance structures for each of the following molecules or ions: a. $\mathrm{HCO}_2^{-}(\mathrm{C}$ is the central atom $)$ b. $\mathrm{N}_2 \mathrm{O}$

Draw resonance structures for each of the following molecules or ions: a. $\mathrm{ClNO}_2$ ( $\mathrm{N}$ is the central atom) b. $\mathrm{OCN}^{-}(\mathrm{C}$ is the central atom)

How many kilojoules are released when $75.0 \mathrm{~g}$ of steam at $100{ }^{\circ} \mathrm{C}$ condenses, cools to $0^{\circ} \mathrm{C}$, and freezes? (Hint: The solution will require three energy calculations.)