The Pauli Exclusion Principle explains various phenomena such as the structure of atoms and how different atoms combine to share electrons. When you have two electrons that are located in the same orbital, the quantum numbers n, l and ml are the same. However, ms will be different. Two electrons cannot have the same four electronic quantum numbers because no more than two electrons may occupy an orbital, and if they do, the spin of one must cancel the spin of the other so their spins will have a zero net spin angular momentum.

Magnesium has an atomic number of 12, so the total number of electrons in its configuration should add up to twelve. The maximum number of electrons in the s subshell is two. Of all the answer choices, only 1s22s22p63s 2 fits the criteria. The sum of the exponent values is 12, matching the atomic number of magnesium, and the number of electrons in the s and p subshells matches the maximum amount possible.

Although it may seem counterintuitive, atomic radius does decrease from left to right on the periodic table. The reason for this is because the added positive charge in the nucleus causes the elctrons to be pulled more strongly towards the center, which decreases the atomic radius.

Intensive properties are not dependent on the amount of substance. Melting point, pressure, temperature, and density are some examples of intensive properties. Therefore, volume of a substance is not an example of an intensive property, rather, it is an extensive property which depends on the amount of substance. Some other examples of extensive properties include weight, energy, and electric charge.

Alkaline earth metals are group II elements; among them, radium has the largest atomic number.

Alkaline earth metals are group II elements; among them, radium has the largest atomic number.

Orbitals are regions in an electron shell where electrons might be located. There are several types of orbitals such as , and . Most elements found on the periodic table contain electrons within one of these orbitals. A characteristic of an orbital is that it can only contain two electrons maximum. A shell might contain multiple orbitals; however, each orbital can only contain two electrons. Each orbital has a unique shape that corresponds to the electron density (the possible location of an electron at a given point in time). The orbital has a spherical shape whereas the orbital has a dumbbell shape. As mentioned, a shell can contain multiple types of orbitals. A shell can typically contain one orbital, three orbitals, five orbitals, and seven orbitals. Remember that the shape of the orbital has no bearing on the amount of orbitals in a shell. An orbital is higher in energy if it is found farther away from the nucleus. The orbitals in order of increasing energy is as follows . Therefore, an orbital has lower energy than a orbital in the same shell.

Intensive properties are not dependent on the amount of substance. Melting point, pressure, temperature, and density are some examples of intensive properties. Therefore, volume of a substance is not an example of an intensive property, rather, it is an extensive property which depends on the amount of substance. Some other examples of extensive properties include weight, energy, and electric charge.

Exergonic reactions release energy; therefore, the energy of products is lower than that of the reactants. Endergonic reactions consume energy; therefore, the energy of products is greater than that of the reactants. In other words, exergonic reactions are spontaneous, while endergonic reactions are nonspontaneous, and require the net input of energy to drive the reaction.

The expression for the relationship between heat () and work () is change in internal energy ():

The work () done by a system is:

with and

Plugging work () into the internal energy equation gives:

Plugging the values given into the internal energy equation gives: