Introductory Topics - College Chemistry

A covalent bond is a bond between two nonmetals, in which electrons are shared. This means that cannot be the correct answer, as sodium is a metal. In fact, is a classic example of an ionic compound.

A polar covalent bond is a bond between two nonmetals in which one nonmetal is more electronegative than the other, pulling the shared electrons toward itself. This occurs in ; chlorine is much more electronegative than hydrogen and pulls the shared electrons toward itself. This gives chlorine a partial negative charge and hydrogen a partial positive charge. is also an example of a polar covalent bond; oxygen is much more electronegative than hydrogen, and each oxygen in a water molecule pulls the shared electrons toward itself. This gives oxygen a partial negative charge and hydrogen a partial positive charge.

A nonpolar covalent bond is a bond between two nonmetals in which electrons are shared equally between the nonmetals. This occurs when the two nonmetals are of equal electronegativity. As the atoms of have the same identity (chlorine), they have the same electronegativity. Thus, electrons are shared equally between the two chlorine atoms--in a nonpolar covalent bond.

Oxygen has a valence of 6, meaning it is looking to form two covalent bonds to complete its octet. Thus, exists as a diatomic molecule joined by a double covalent bond. and are held together by single covalent bonds, and is held together by a triple covalent bond.

Dipole-dipole interactions are the weakest because they are the result of attractions between weak partial charges

Hydrogen bonds are a special type of dipole-dipole interaction, but they are much stronger.

An ionic bond is the result of the complete transfer of electrons from on atom to another. This results in a positive charge on one atom and a negative charge on the other. The charges on these ions are much stronger than in dipoles. The two oppositely charged atoms are held together by electrostatic attraction.

Atoms that are part of a covalent bond share electrons. This makes the atoms harder to separate and, therefore, the bond is very strong.

For this question, we're asked to determine which answer choice represents a compound with a total of six covalent bonds.

To answer this, we'll need to know the structure of each of the compounds. Moreover, it's important to remember that double bonds count as two covalent bonds.

Both sulfuric acid and phosphoric acid have a total of eight covalent bonds, while nitric acid has five. Carbonic acid is the only one shown that contains six covalent bonds, making it the correct answer.

Cadmium normally has electrons, but only has electrons.

The normal electron configuration for is as follows:

Since the cadmium is losing electrons, it must lose them from the highest energy shell. In this case, this means the cadmium will be losing its electrons in .

Thus, the electron configuration for is .

The normal electron configuration for is as follows:

Since it is losing electrons, the element must lose the electrons from the highest energy shell first. Thus, the element loses electrons from and electron for .

The electron configuration for is then

Start by finding the noble gas core. For iron, this will be argon as this is the noble gas that is closest to it.

Next, recall that since the orbitals are higher in energy that the orbitals, electrons will be lost from the orbital first.

The normal electron configuration for is as follows:

has lost electrons. It will lose the first two electrons from the shell, then it will lose electron from the shell, giving it the following electron configuration:

Start by finding the noble gas core. For tungsten, this will be xenon as this is the noble gas that is closest to it.

The normal electron configuration for is as follows:

Recall that electrons are lost in the highest energy level subshell first.

has lost electrons. It will lose the first two electrons from the shell, then it will lose electron from the shell, giving it the following electron configuration:

Electrons of an atom are located within electronic orbitals around a nucleus. The electrons of each atoms have their own specific energy level called principal energy level. When electrons are excited by absorbing energy the electrons can jump to a high energy level. Then when an electron drops back to a lower energy level the electron emits the energy. Therefore, when an atom moves from a lower energy state to a higher energy state. the electrons absorb energy.

Each element has a unique electron configuration that represents the arrangement of electrons in orbital shells and sub shells. There are four different orbitals, s, p, d, and f that each contain two electrons. The p, d, and f orbitals contain subshells that allow them to hold more electrons. The orbitals for an element can be determined using the periodic table. The s-block consists of group 1 and 2 (the alkali metals) and helium. The p-block consists of groups 3-18. The d-block consists of groups 3-12 (transition metals), and the f-block contains the lanthanides and actinides series. Using this information we can determine the full electron configuration of sodium.

To do this, start at hydrogen located at the top left of the periodic table. Hydrogen and helium are in the first s orbital and account for . Next, we move to the second s-orbital that contains lithium (Li) and beryllium (Be), which accounts for . Then we move to boron, carbon, nitrogen, oxygen, fluorine, and neon, which are all in the p-block and account for . There is no 1p orbital. Finally, we are at sodium, which is in the s-block and accounts for . Therefore the full electron configuration of sodium is .

Each element has a unique electron configuration that represents the arrangement of electrons in orbital shells and subshells. There are four different orbitals, s, p, d, and f that each contain two electrons. The p, d, and f orbitals contain subshells that allow them to hold more electrons. The orbitals for an element can be determined using the periodic table. The s-block consists of group 1 and 2 (the alkali metals) and helium. The p-block consists of groups 3-18. The d-block consists of groups 3-12 (transition metals), and the f-block contains the lanthanides and actinides series. Using this information we can determine the electron configuration of iodine in nobel gas configuration.

The nobel gas configuration is a short hand to writing out the full electron configuration. To do this, start at the nobel gas that come before the element of interest. In the case of iodine, the nobel gas is krypton. Therefore, the electron configuration will begin with , and this will be the new starting place for the electron configuration.

After krypton comes the s-block, which contains elements with the atomic numbers 37 and 38 that account for . Then comes the d-block containing elements 39-48 that account for . Finally comes the p-block containing elements 49-53 that account for . Therefore, the electron configuration of iodine in nobel gas configuration is .

Molarity has no determination in whether an acid or base is strong or weak. Rather, molarity specifies the concentration of hydroxide or hydrogen ions in a solution. Weak Acids do not completely dissociate in water, while strong acids do. Polyprotic acids, those with more than one proton to donate, do not necessarily determine if an acid is strong (e.g. hydrochloric acid is an example of a strong, monoprotic acid).

is an ionic compound because it is composed of a metal and a nonmetal.

is a molecular compound because it consists of a nonmetal connected to another nonmetal.

Xenon is an atomic element because its elemental form consists of one atom.

In order to answer this question correctly, you must remember the different types of intermolecular forces and their effects.

only contains London dispersion forces. Since it is a smaller molecule compared to the others, it cannot have the highest boiling point.

also only contains London dispersion forces. However, since it is a bigger molecule, it will have a higher boiling point than .

While contains both London dispersion forces and dipole-dipole interactions, it lacks hydrogen boding as the fluorine atom is attached directly to the second carbon.

has the highest boiling point because it contains London dispersion forces, dipole-dipole interactions, and hydrogen bonding.

A hydrogen bond refers to the attraction between a hydrogen attached to an electronegative atom of one molecule and an electronegative atom of another molecule. The atoms which commonly form hydrogen bonds are oxygen, nitrogen, and fluorine, which are very electronegative. When a hydrogen bond forms between hydrogen and one of these three atoms, hydrogen gains a partial positive charge while the electronegative atom gains a partial negative charge. Carbon is not a very electronegative atom and thus cannot form a hydrogen bond.

London dispersion forces are the weakest of the three. Every molecule is composed of electrons, which are free to move around. This can create a temporary charge, on any molecule, at any time. When two molecules come close together, their varying charges can orient such that one end of a molecule may be slightly positive, while the end of a nearby molecule may be slightly negative. This leads to a slight attraction between the two molecules, called London dispersion forces until they move around again. This is a weak, temporary force.

Dipole-dipole interactions develop when polar compounds line up and are attracted to each other. These forces are stronger than London dispersion forces due to the permanency of the dipoles, but weaker than hydrogen bonds.

Hydrogen bonds are the strongest force of the three. The name refers to the attractive force between the hydrogen attached to one electronegative atom (usually oxygen, nitrogen, or fluorine) and an electronegative atom of a different molecule. The electronegative atom gains a partial negative charge, while the hydrogen gains a partial positive charge. These forces are responsible for many of the qualities of water.

Drawing the Lewis Diagrams for these molecules reveals that the C-N bond in is a triple covalent bond, whereas the C-N bonds in and are double covalent bonds and the C-N bond in is a single covalent bond. Triple covalent bonds between two given atoms are always stronger than double bonds between these same two atoms, and similarly double bonds are even stronger than single bonds. Bond length is inversely related to bond strength; therefore a shorter bond is a stronger bond, and triple covalent bonds are shorter than either double or single covalent bonds. Thus, the C-N bond in is the shortest in length.