Chapter 4: The Periodic Table pg 123 #1-15, pg 131 #1-8, pg 142 #1-14, pg 148 #1-11

Pg 123 #1-15 1. State the periodic law. The physical and chemical properties of the elements are periodic functions of their atomic numbers. 2. What do elements in a period have in common? Elements in a group? Elements in a period have the same core-electron configuration. Elements within a group have the same outer electron configuration, and they also share common properties.

Pg 123 #1-15 (cont.) 3. What contribution did Moseley make to the development of the periodic table? Moseley realized that the X-ray spectra of the elements correlated with the atomic number of the elements and not the atomic mass. When the elements were arranged according to atomic number, the discrepancies in Mendeleev’s periodic table disappeared.

Pg 123 #1-15 (cont.) 4. Write the atomic numbers and symbols for each of the following elements. a. silver 47 Ag g. palladium 46 Pd b. gold 79 Au h. radon 86 Rn c. mercury 80 Hg i. radium 88 Ra d. copper 29 Cu e. zinc 30 Zn f. platinum 78 Pt

Pg 123 #1-15 (cont.) 5. Which element in item 4 has the greatest atomic mass? The least atomic mass? Greatest: Radium; Least: Copper

Pg 123 #1-15 (cont.) 6. Round the atomic masses for each element listed in item 4 to the hundredths place. a. silver 107.87 f. platinum 195.08 b. gold 196.97 g. palladium 106.42 c. mercury 200.59 h. radon 222.02 d. copper 63.55 i. radium 226.03 e. zinc 65.39

Pg 123 #1-15 (cont.) 7. What is the name of the elements located between the metals and nonmetals in the periodic table? semiconductors 9. Which elements are considered the most stable? Why? Noble gases; each noble gas has a filled octet.

Pg 123 #1-15 (cont.) 10. What is produced when halogens combine with alkali metals? salt 11. Why do groups of main-block elements display similar chemical behaviors? All of the elements in a group have the same outer-level electron configuration.

Pg 123 #1-15 (cont.) 12. What do you expect the electron configuration of element 112 to be? 7s25f146d10 13. Explain what the transition metals have in common with respect to their electron configurations? The outermost electrons in transition metals are in s orbitals and d orbitals, specifically, ns and (n – 1)d orbitals, which are close in energy. A few have no s electrons.

Pg 123 #1-15 (cont.) 14. What features do the halogens have in common? The noble gases? The halogens are reactive and combine with metals to form salts. By gaining one electron, they achieve a stable octet and become -1 ions. Noble gases are unreactive and have stable octets of s and p electrons in the outer energy level. 15. Why is hydrogen placed in a group by itself? Hydrogen has only 1 proton and 1 electron, and its behavior does not match that of any of the groups of elements.

Pg 131 #1-8 1. What is the difference between a metal and a nonmetal? A metal is a good conductor of electricity, while a nonmetal is not. 2. Why is copper used in electrical wiring? Would gold or aluminum be a better choice? Explain. Copper is used in electrical wiring because it is an excellent conductor of electricity, resists corrosion, and is inexpensive.

Pg 131 #1-8 (cont.) 3. Define what is meant by malleability and ductility. Ductility is the capacity to be squeezed out into a wire. Malleability is the capacity to be hammered or pressed into sheets. 4. Identify the one property that all metals share. Electrical conductivity

Pg 131 #1-8 (cont.) 5. How is an alloy made? Alloys can be made by melting metals together. Sometimes non-metals are included. 6. What are crystals? A crystal is a form of matter in which the molecules, ions, or atoms of a crystal are arranged in an orderly geometric pattern that repeats in 3 dimensions.

Pg 131 #1-8 (cont.) 7. Explain the difference in the conduction bands of metals, nonmetals, and semiconductors. In metals, the conduction bands are low in energy, and electrons are easily excited into those bands. In semiconductors, the conduction bands are of higher energy, so more energy is required to excite electrons into those bands. Therefore, semiconductors are less conducive than metals. In nonmetals, the conduction bands are very high in energy, so it is very difficult to excite electrons into them. Therefore, nonmetals are poor conductors.

Pg 131 #1-8 (cont.) 8. Which electrons form the bonds that bind atoms of an element together in a crystal? The outer electrons

Pg 142 #1-14 1. Why is it difficult to measure the size of an atom? Atoms are very small, and there is no definite boundary to the electron cloud. 2. What does the term atomic radius mean? Atomic radius means “bond radius,” half the distance between the nuclei of bonded atoms.

Pg 142 #1-14 (cont.) 3. What is the difference between bond radius and van der Waals radius? Van der Waals radius is half the distance between the adjacent unbonded atoms. 4. What is ionization energy? Ionization energy is the amount of energy needed to remove an electron from an atom.

Pg 142 #1-14 (cont.) 5. What periodic trends exist for ionization energy? What exceptions exist in these trends? Ionization energy generally increases from left to right across a period and decreases from top to bottom in a group. Group 2 and Group 15 elements have higher ionization energies than the trend would indicate.

Pg 142 #1-14 (cont.) 6. What is electron affinity? How is it different from ionization energy? Electron affinity is the energy given off when an electron is added to an atom. Electron affinity involves adding an electron to an atom rather than taking one away. 7. What periodic trends exist for electron affinity? Electron affinities generally increase (in negative value) across a period and decrease (in negative value) moving down through a group.

Pg 142 #1-14 (cont.) 8. What trends are evident in atomic size as you proceed down a group of elements? How do each of these trends progress as you move across a period? Atomic size increases, ionization energy decreases, and electron affinity decreases from top to bottom in a group. Atomic size decreases, ionization energy increases, and electron affinity increases from left to right across a period.

Pg 142 #1-14 (cont.) 9. Define the term electron shielding. Electron shielding occurs when underlying levels of electrons reduce the attraction of the nucleus for the outermost electrons. 10. What effect does electron shielding have on atomic size? on ionization energy? on electron affinity? Electron shielding increases atomic size, decreases ionization energy, and decreases electron affinity.

Pg 142 #1-14 (cont.) 11. What happens when an atom gains an extra electron? The atom becomes a negatively charged ion. 12. The periodicity of melting and boiling points in Period 6 is the result of the addition of electrons to which orbitals? Electrons are added to 6s, 5d, and 6p orbitals.

Pg 142 #1-14 (cont.) 13. When an atom loses an electron, what is its charge? What do you think happens to the size of the atom? The ion formed has a +1 charge. The atom becomes smaller. 14. When an atom gains an electron, what is its charge? What do you think happens to its size? The ion formed has a -1 charge. The atom becomes larger.

Pg 148 #1-11 1. Define the term naturally occurring element. Where are these elements located in the periodic table? Naturally occurring elements are those that can be found in the universe. With few exceptions, the naturally occurring elements are found in the first six periods of the periodic table. 2. How and where were the naturally occurring elements created? They are produced by fusion reactions in stars.

Pg 148 #1-11 (cont.) 3. What element is the building block for all other natural elements? hydrogen 4. What is a synthetic element? A synthetic element is made by the bombardment of another element with neutrons, protons, or other atomic nuclei.

Pg 148 #1-11 (cont.) 5. What is a nuclear reaction? A nuclear reaction causes changes to the number of protons and neutrons in an atom’s nucleus. The nucleus usually transmutes to a different element. 6. What is transmutation? The process by which on nucleus changes into another by radioactive disintegration or bombardment with other particles.

Pg 148 #1-11 (cont.) 7. In the first observed transmutation, nitrogen was bombarded with alpha particles to produce a hydrogen nucleus. The other product was an ion of which element? oxygen-17

Pg 148 #1-11 (cont.) 8. How do scientists use cyclotrons to create synthetic elements? The cyclotron accelerates charged particles to high energies. The particles are allowed to collide with existing nuclei, changing them to other nuclei. 9. How are superheavy elements prepared? By bombarding nuclei of heavy elements with heavy ions from accelerates to cause a nuclear reaction to form an element with an atomic number greater than 106.

Pg 148 #1-11 (cont.) 10. What do scientists mean by the term island of stability with respect to superheavy synthetic elements? Nuclei of atomic number 114 may be stable if they can be produced. 11. What synthetic element was discovered in 1982? Meitnerium