Energy levels and sublevels

When you consider that atoms of the heaviest elements contain in excess of 100 electrons, that there are numerous principal energy levels and sublevels and their corresponding orbitals, and that each orbital may contain a maximum of two electrons, the idea of determining the arrangement of an atom s electrons seems daunting. Fortunately, the arrangement of electrons in atoms follows a few very specific rules. In this section, you ll learn these rules and their occasional exceptions. 

Electromagnetic spectra provide information about energy levels and sublevels in an atom. 

Energy Levels and Sublevels Principal Energy Levels... 

O Reading Check Explain the relationship between energy levels and sublevels. 

The electron configuration of an atom, the distribution of electrons into its energy levels and sublevels, ultimately determines the behavior of the element. (Section 8.1)... 

For each principal energy level there are one or more sublevels. They are the s, p, d, and / sublevels, using initial letters that come from terms formerly used in spectroscopy, the study of the interaction of matter and electromagnetic radiation. A specific sublevel is identified by both the principal energy level and sublevel. Thus the p sublevel in the third principal energy level is the ip sublevel. An electron that is in the ip sublevel may be referred to as a 3p electron. ... 

Complete the following table with the energy level and sublevels ... 

The electron configuration for an atom specifies the energy levels and sublevels occupied by the electrons of an atom. 

The quantum mechanics model is more modern and more mathematical. It describes a volume of space surrounding the nucleus of an atom where electrons reside, referred to earlier as the electron cloud. Similar to the Bohr model, the quantum mechanics model shows that electrons can be found in energy levels. Electrons do not, however, follow fixed paths around the nucleus. According to the quantum mechanics model, the exact location of an electron cannot be known, but there are areas in the electron cloud where there is a high probability that electrons can be found. These areas are the energy levels each energy level contains sublevels. The areas in which electrons are located in sublevels are called atomic orbitals. The exact location of the electrons in the clouds cannot be precisely predicted, but the unique speed, direction, spin, orientation, and distance from the nucleus of each electron in an atom can be considered. The quantum mechanics model is much more complicated, and accurate, than the Bohr model. 

The quantum mechanical model of atomic structure is far too difficult to be explained in detail in an AP Chemistry course. However, some aspects of the theory are appropriate, and you should know them. These include the predicted number and shapes of orbitals in each energy level the number of electrons found in each orbital, sublevel, and energy level and the meaning of the four quantum numbers. 

For molecules, the spectroscopic nomenclature for molecular energy levels and their vibronic and rotational sublevels is messy and very specialized. Already for homonuclear or heteronuclear diatomic molecules a new quantum number shows up, which quantifies the angular momentum along the internuclear axis, but the reader need not be burdened with the associated nomenclature. 

Each sublevel has its own energy. Examine Figure D.3 to see the relative energies of the levels and sublevels. 

Figure 7.5 shows a diagram of the first three energy levels and an inside view of the sublevels within them. Notice how... 

Table 11.1 Possible Sublevels and Orbitals for the First Seven Principal Energy Levels (The sublevels In parentheses are not necessary for describing any of the known elements.)...

Because atomic numbers 13 through 18 are in the p block, we know they go into a p sublevel. Because the p sublevels begin on the second principal energy level and atomic numbers 13 through 18 are in the second row of the p block, the 13 through 18 electrons must go into the 5p sublevel. 

How many sublevels are in the fourth principal energy level for the hydrogen atom What is the shorthand notation used to describe them (For example, there is one sublevel in the first principal energy level, and it is described as It.)... 

We specify both the principal energy level and type of sublevel when describing the location of an electron—for example. Is, 2s, 2p. Energy level designations for the first four principal energy levels follow ... 

Distinguish between a principal energy level and a sublevel. 

The electron s wave function (iK atomic orbital) is a mathematical description of the electron s wavelike behavior in an atom. Each wave function is associated with one of the atom s allowed energy states. The probability density of finding the electron at a particular location is represented by An electron density diagram and a radial probability distribution plot show how the electron occupies the space near the nucleus for a particular energy level. Three features of an atomic orbital are described by quantum numbers size (n), shape (/), and orientation (m/). Orbitals with the same n and / values constitute a sublevel sublevels with the same n value constitute an energy level. A sublevel with / = 0 has a spherical (s) orbital a sublevel with / = 1 has three, two-lobed (p) orbitals and a sublevel with / = 2 has five, multi-lobed (d) orbitals. In the special case of the H atom, the energy levels depend on the n value only. 

Describe the importance of the spin quantum number (m,) and the exclusion principle for populating an orbital understand how shielding and penetration lead to the splitting of energy levels into sublevels ( 8.2) (EPs 8.4-8.13)... 

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