Use VSEPR theory to predict the structure of these polyatomic ions:

(a) sulfate ion
(b) chlorate ion
(c) periodate ion

In which general areas of the periodic table are the elements with (a) the highest and (b) the lowest electronegativities located?

Determine whether the following atoms will form an ionic compound or a molecular compound, and give the formula of the compound.

(a) sodium and chlorine
(b) carbon and 4 hydrogen
(c) magnesium and bromine
(d) 2 bromine
(e) carbon and 2 oxygen

Classify the bond between these pairs of elements as principally ionic or principally covalent:

(a) sodium and oxygen
(b) nitrogen and hydrogen
(c) oxygen and hydrogen
(d) phosphorus and chlorine

Chlorine gas can be prepared according to the reaction

$$\begin{aligned} &16\mathrm{~HCI}+2\mathrm{~KMnO}_4 \longrightarrow \\ &5\mathrm{~Cl}_2+2\mathrm{~KCl}+2\mathrm{~MnCl}_2+8 \mathrm{~H}_2\mathrm{O} \\ & \end{aligned}$$

(a) How many moles of $\mathrm{MnCl}_2$ can be produced when $25 \mathrm{~g}$ $\mathrm{KMnO}_4$ are mixed with $85 \mathrm{~g}\mathrm{~HCl}$?
(b) How many grams of water will be produced when $75 \mathrm{~g}$ $\mathrm{KCl}$ are produced?
(c) What is the percent yield of $\mathrm{Cl}_2$ if $150 \mathrm{~g} \mathrm{~HCl}$ are reactcd, producing $75 \mathrm{~g}$ of $\mathrm{Cl}_2$?
(d) When $25 \mathrm{~g} \mathrm{HCl}$ react with $25 \mathrm{~g} \mathrm{~KMnO}$, how many grams of $\mathrm{Cl}_2$ can be produced? (e) How many grams of the excess reactant in part (d) are left unreacted?

Explain the large increase in ionization energy needed to remove the third electron from beryllium compared with that needed for the second electron.

Hydrazine $\left(\mathrm{N}_2 \mathrm{H}_4\right)$ and hydrogen peroxide $\left(\mathrm{H}_2 \mathrm{O}_2\right)$ have been used as rocket propellants. They react according to the following equation:

$$7\mathrm{~H}_2 \mathrm{O}_2+\mathrm{N}_2 \mathrm{H}_4 \longrightarrow 2 \mathrm{~HNO}_3+8 \mathrm{~H}_2 \mathrm{O}$$

(a) When $75 \mathrm{~kg}$ of hydrazine react, how many grams of nitric acid can be formed?
(b) When $250 \mathrm{~L}$ of hydrogen peroxide $(d=1.41 \mathrm{~g} / \mathrm{mL}$ ) react, how many grams of water can be formed?
(c) How many grams of hydrazine will be required to react with $725 \mathrm{~g}$ hydrogen peroxide?
(d) How many grams of water can be produced when $750 \mathrm{~g}$ hydrazine combine with $125\mathrm{~g}$ hydrogen peroxide?
(e) How many grams of the excess reactant in part (d) are left unreacted?

Determine whether each of the following atoms will form a nonpolar covalent compound or a polar covalent compound, and give the formula of the compound.

(a) 2 oxygen
(b) hydrogen and bromine
(c) oxygen and 2 hydrogen
(d) 2 iodine

Pick the electron structures that represent elements in the same chemical family:

(a) $1 s^2 2 s^1$
(b) $1 s^2 2 s^2 2 p^4$
(c) $1 s^2 2 s^2 2 p^2$
(d) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^4$
(e) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^6$
(f) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2$
(g) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^1$
(h) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^1$

What do the electron structures of the alkali metals have in common?

Using the table of electronegativity values, indicate which element is more positive and which is more negative in these compounds:

(a) $\mathrm{HCl}$
(b) $\mathrm{LiH}$
(c) $\mathrm{CCl}_4$
(d) $\mathrm{IBr}$
(e) $\mathrm{MgH}_2$
(f) $\mathrm{OF}_2$

The atomic numbers of the noble gases are $2,10,18,36,54$ and $86$. Without looking at a periodic table, determine the atomic numbers for the elements that have five electrons in their valence shell.

Write an equation representing each of the following :

(a) the change of a magnesium atom to a magnesium ion
(b) the change of a bromine atom to a bromide ion

Which one in each pair has the larger radius? Explain.

(a) a calcium atom or a calcium ion
(b) a chlorine atom or a chloride ion
(c) a magnesium ion or an aluminum ion
(d) a sodium atom or a silicon atom
(e) a potassium ion or a bromide ion