Which of the following occurs upon moving from left to right across a period (row) of elements on the periodic table?
The principal quantum number increases.
The principal quantum number decreases.
The number of core electrons changes.
The effective nuclear charge increases.
answer
The effective nuclear charge increases.
question
Which list correctly gives atoms in order of increasing size?
Which list correctly gives atoms in order of increasing size?
Cl < P < Xe < Br
P < Cl < Br < Xe
Cl < P < Br < Xe
Xe < Br < P < Cl
answer
Cl < P < Br < Xe
question
Which of the following shows a correct relationship between first ionization energies of the given atoms?
Which of the following shows a correct relationship between first ionization energies of the given atoms?
Li > Be
Ne > F
Xe > Ne
Ga > Ge
answer
Ne > F
question
Effective Nuclear Charge
answer
The net positive charge experienced by an electron in a many-electron atom; this charge is not the full nuclear charge because there is some shielding of the nucleus by the other electrons in the atom; Z eff
The effective nuclear charge is always less than the actual nuclear charge (Zeff
question
Electron affinity
answer
the measure of the attraction of an electron toward an isolated gaseous atom. When an electron is added to an isolated gaseous atom or ion energy is either released or absorbed; this energy change is known as electron affinity. Electron affinity is positive when energy is absorbed, and it is negative when energy is released.
question
Which of the following correctly describes the measurement of an atom's electron affinity?
Which of the following correctly describes the measurement of an atom's electron affinity?
It measures the ease with which an atom gains an electron.
It is a positive value.
It is a measure of the ease with which an atom loses an electron.
It is a measurement of the energy change associated with forming a positively charged ion from a neutral atom.
answer
It measures the ease with which an atom gains an electron.
question
List the seven elements that exist as diatomic molecules under normal conditions
answer
H2, N2, O2, F2, Cl2, Br2, I2
question
Metalloids have properties intermediate between those of metals and nonmetals. An example of a metalloid is _____.
Al
I
Sb
P
answer
Sb
question
Which halogen is a liquid at room temperature?
Which halogen is a liquid at room temperature?
bromine
iodine
mercury
fluorine
answer
bromine
question
The experimentally measured and generally accepted value for the molar volume of Na is about 23 cm3/mol. Which of the following best explains why the value calculated in Part B is significantly smaller than the measured values?
The experimentally measured and generally accepted value for the molar volume of is about 23 . Which of the following best explains why the value calculated in Part B is significantly smaller than the measured values?
-The molar volume calculated does not take into account that the electron clouds of neighboring sodium atoms repel each other.
-The metallic radius used in the calculation was based on a small overlap between the electron orbitals of neighboring atoms.
-The metallic radius for sodium does not take into account that sodium commonly loses one electron and exists as Na+.
-The molar volume calculated does not take into account that the shape of the sodium atoms affects packing space between atoms.
-The metallic radius reported is not very accurate since electron clouds are mostly empty space and have no specific volume.
answer
The molar volume calculated does not take into account that the shape of the sodium atoms affects packing space between atoms.
When spheres pack into a volume of space, some free space is left between adjacent particles. Think of a box of marbles. Marbles do not completely fill the space of their container. Although each marble is in contact with its neighbor, some space or holes are left between each marble. The packing of spherical atoms is similar in that some free space is left when the atoms pack together. To properly calculate the molar volume of a solid you must take into account how the atoms pack and the space left between them.
question
Which would you expect to experience a greater effective nuclear charge?
Which would you expect to experience a greater effective nuclear charge?
a 2p electron of a Ne atom
a 3s electron of a Na atom
answer
a 2p electron of a Ne atom
question
How do cations of the same charge change in radius as you move down a column in the periodic table?
answer
They get larger, just like the atoms do.
question
Which would you expect to be greater?
Which would you expect to be greater?
I2 for a carbon atom
I1 for a boron atom
answer
Zeff nuclear charge, increases across a period and Boron goes before Carbon, which means Carbon has a greater Zeff. If Carbon had a greater Zeff before, now would be even greater, since 6 prontons exerting force over its four remaining electrons.
If you notice, also B^+ and C^+2, the products of the ionization energies, have the same number of electrons, which mean they are an isoelectronic series.
--- increasing nuclear charge ( atomic number)--->
B^+ C^+2
--- Decreasing ionic radius--->
Meaning harder time to pull the other electrons from the tightly bound to the nucleus Carbon
question
Why it is easier to remove a 2p electron from an oxygen atom than from a nitrogen atom.
answer
There is more electron-electron repulsion in the case of oxygen because two electrons have to occupy the same orbital.
question
Do Cr3+ and V2+ have the same or different electron configurations?
answer
same
Cr = {AR} 4s2, 3d4 C3r+ = 3d3
V = {Ar} 4s2, 3d3 V2+ = 3d3
question
What is the relationship between the value for the first ionization energy of a Cl−(g) ion and the electron affinity of Cl(g)?
answer
The numbers are the same; the signs are opposite
question
Representative oxidation states of the elements. Note that hydrogen has both positive and negative oxidation numbers, +1 and -1. The red stepped line divides metals from nonmetals.
How are common oxidation states divided by this line?
answer
Anions are above the line; cations are below the line.
question
Bonding Atomic Radius
answer
The radius of an atom as defined by the distances separating it from other atoms to which it is chemically bonded
question
Which part of the periodic table has the elements with the largest elements?
answer
Increases right to left and from top to bottom
question
How to solve for predicting the lengths of bonds
answer
Use figure 7.7; bond length is the sum of bonding atomic radii
question
Periodic trends in atomic radii
answer
1. within each group, bonding atomic radius tends to increase from top to bottom
2. Within each period bonding atomic radius tends to decrease from left to right
(minor exceptions include Cl to Ar and As to Se)
question
Isoelectronic Series
answer
A series of atoms, ions, or molecules having the same number of electrons
question
Ionization Energy
answer
The energy to remove an electron from a gaseous atom when the atom is in its ground state
question
Perodic Trends in first Ionization Energies
answer
1. I1 generally increases as we move across a period
2. I1 generally decreases as we move down any column in the periodic table
3. The s- and p-block elements show a larger range of I1 values than do the transition metal elements
question
Trends in ionization energy
answer
Increase up and to the right
Bottom of d block is exception- larger values on bottom of d block than on the top of d block
question
The important difference between electron affinity and ionization energy
answer
Ionization energy measures the energy change when an atom loses an electron and electron affinity measures the energy change when atom gains an electron
question
Electron affinity
answer
The energy change that occurs when an electron is added to a gaseous atom or ion
question
Of electron affinity and ionization energy, which has a positive energy change and which has a negative energy change?
answer
electron affinity gains an electron so it has a negative energy change (energy must be given to gain an electron)
ionization energy loses an electron so has a positive energy change (energy must be absorbed to remove an electron)
question
Metallic Character
answer
The extent to which an element exhibits the physical and chemical properties characteristic of metals, for example, luster, malleability (can be pounded into thin sheets), ductility (can be drawn into wire), and good thermal and electrical conductivity
on the periodic table: increases right to left and down
question
Alkali Metals
answer
Members of group 1A in the periodic table
question
Alkaline Earth Metals
answer
Members of group 2A in the periodic table
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