chem extra credit ch

The periodic trend for electron affinity values is not as consistent as for other trends. Which statement best describes the trend?

Electron affinity becomes more negative going from left to right but does not have a clear trend going from top to bottom for most columns.

Which pair gives the more metallic element first?

K, Li

One of several trends found in the periodic table relates to ionization energy. Ionization energy is the amount of energy required to remove an electron from an atom. In the process, a cation, or positively charged ion, is formed. Which element has the smallest ionization energy?

K, potassium

Additional energy is required to move second and successive electrons from an ion. Which element could have the following series of ionization energies (IE)? IE1 = 738 kJ/mol; IE2 = 1450 kJ/mol; IE3 = 7730 kJ/mol; IE4 = 10545 kJ/mol; IE6 = 17995 kJ/mol

Magnesium

Which pair lists the element with the lower first ionization energy first?

Oxygen, fluorine

One of several trends found in the periodic table relates to the atomic radius or the size of an atom. The radius is measured by the distance the outer edge of the electron cloud is from the nucleus. The outer edge is the last set of orbitals containing the valence electrons. Which of the following elements has the largest atomic radius?

Rubidium, Rb

The effective nuclear charge is the amount of charge experienced by an electron taking into account any shielding effects from other electrons. Electrons between the nucleus and the electron of interest cause shielding and reduce the actual charge felt by the electron of interest. The outermost electron of boron experiences a lower effective nuclear charge than carbon. Why?

The nuclear charge increases from boron to carbon, but there is no additional shielding.

Alkali metals show trends, such as electron affinity and melting point, that are not typically seen in other groups of metals. Moving from lithium to cesium, the melting point _____ and the electron affinity becomes _____.

decreases; more positive

Group 7A, the halogens, show periodic trends with respect to their melting point, boiling point, and density. As you move down the column, the melting and boiling points _____ and the density _____.

increase; increases

Ions result from the gain or loss of one or more electrons. The change in the number of electrons results in a change in size for the ion as compared to the neutral atom. Anions are _____ than their neutral parent atom, and cations are _____ than their neutral parent atom.

larger; smaller

The effective nuclear charge is the amount of charge experienced by an electron taking into account any shielding effects from other electrons. Electrons between the nucleus and the electron of interest cause shielding and reduce the actual charge felt by the electron of interest. Compare the outermost electron in each of the following atoms. Which one will experience the smallest effective nuclear charge?

potassium

Why are the electron affinity values for the noble gases endothermic?

An electron added to a noble gas must go in the next higher energy level.

Elements have a series of ionization energies for removing the first and additional electrons from the atom. Each ionization energy increases for successive electrons being removed. Where will the largest jump in ionization energies occur for aluminum?

Between the third and fourth ionization energies

Select the true statement.

Cations are smaller than their neutral parent atoms because there are fewer electrons "competing" for the attractive force of the protons in the nucleus.

Electron affinity is the energy associated with the gain of an electron by an atom in the gaseous state. Which element will release the most energy when gaining an electron?

Chlorine

Which element is the most metallic?

Cs

Noble gases are named as such because they are very unreactive. However, a few compounds are known to form with krypton and xenon. Which element will react with these noble gases to form compounds?

Fluorine

Which element requires the most energy to lose one electron?

Helium

Which one of the following statements is true regarding ionization energies?

Ionization energies are all endothermic.

One of several trends found in the Periodic Table relates to the atomic radius (the size of an atom). The radius is calculated by measuring the distance between the outer edge of the electron cloud and the nucleus. The outer edge is the last set of orbitals containing the valence electrons. Which one of the following has the smallest atomic radius?

Sulfur

One of several trends found in the periodic table relates to the atomic radius or the size of an atom. The general trend in atomic radius is that moving down the periodic table, the size increases; moving across the periodic table from left to right, the size decreases. Therefore, rubidium has the largest atomic radius whereas helium has the smallest. Trends in the atomic radius showing that moving down the periodic table, size increases, whereas moving across the periodic table from left to right, size decreases. What factor causes the atomic radius to increase while moving down the periodic table, from top to bottom?

The number of electron shells increase.