Chapter 6

Explain the octet rule. Why are hydrogen and helium exceptions to the octet rule?

How many valence electrons do elements in group 1 have? In group 18

Sport Bottles Some sports bottles are made of Lexan, a plastic containing a compound of the elements chlorine, carbon, and oxygen. Order these elements from greatest to least according to atomic radius and ionic radius.

Contact Lenses Soft contact lenses are made of silicon and oxygen atoms bonded together. Create a table listing the atomic and ionic electron configurations, and the atomic and ionic radii for silicon and oxygen. When silicon bonds with oxygen, which atoms become larger and which become smaller? Why?

Artificial Sweetener Some diet sodas contain the artificial sweetener aspartame, a compound containing carbon, nitrogen, oxygen, and other atoms. Create a table showing the atomic and ionic radii of carbon, nitrogen, and oxygen. (Assume the ionization states shown in Figure \(6.14 .\) ) Use the table to predict whether the sizes of carbon, nitrogen, and oxygen atoms increase or decrease in size when they form bonds in aspartame.

Define an ion.

Explain why the radius of an atom cannot be measured directly.

What is the metalloid in period 2 of the periodic table that is part of compounds used as water softeners?

Do you expect cesium, a group 1 element used in infrared lamps, or bromine, a halogen used in firefighting compounds to have the greatest electronegativity? Why?

Which element in each pair is more electronegative? a. \(K,\) As \(\quad\) b. N, Sb \(\quad\) c. Sr, Be

Explain why the s-block of the periodic table is two-groups wide, the p-block is six-groups wide, and the d-block is ten-groups wide.

Most of the atomic masses in Mendeleev's table are different from today's values. Explain why.

Arrange the elements oxygen, sulfur, tellurium, and selenium in order of increasing atomic radii. Is your order an example of a group trend or a period trend?

Milk The element with the electron configuration \([\mathrm{Ar}] 4 \mathrm{s}^{2}\) is an important mineral in milk. Identify this element's group, period, and block in the periodic table.

Why are there no p-block elements in the first period?

Jewelry What are the two transition metals that are used in making jewelry and are the group 11 elements with the lowest atomic masses?

Apply Sodium forms a \(1+\) ion, while fluorine forms a \(1-\) ion. Write the electron configuration for each ion. Why don't these two elements form \(2+\) and \(2-\) ions, respectively?

Generalize The outer-electron configurations of elements in group 1 can be written as \(n \mathrm{s}^{1}\) , where \(n\) refers to the element's period and its principal energy level. Develop a similar notation for all the other groups of the representative elements.

Define matter. Identify whether or not each of the following is a form of matter. (Chapter 1\()\) $$\begin{array}{ll}{\text { a. microwaves }} & {\text { d. velocity }} \\\ {\text { b. helium inside a balloon }} & {\text { e. a speck of dust }} \\\ {\text { c. heat from the Sun }} & {\text { f. the color blue }}\end{array}$$

How is the energy of a quantum of emitted radiation related to the frequency of the radiation? (Chapter 5 )

What element has the ground-state electron configuration of \([\mathrm{Ar}] 4 \mathrm{s}^{2} 3 \mathrm{d}^{6} ?(\text { Chapter } 5)\)

Triads In the early 1800s, German chemist J. W. Dobereiner proposed that some elements could be classified into sets of three, called triads. Research and write a report on Dobereiner’s triads. What elements comprised the triads? How were the properties of elements within a triad similar?

Affinity Electron affinity is another periodic property of the elements. Write a report on what electron affinity is, and describe its group and period trends.

Mendeleev placed the noble gases on the left of his table. Why does placement on the right of the modern table make more sense?

Most of the atomic masses in Mendeleev's table differ from today's values. Why do you think this is so?