The lowest-energy arrangement, or ground-state electron configuration, of an atom is a list of the orbitals occupied by its electrons. We can predict this arrangement by following three rules. RULE 1The lowest-energy orbitals fill up first, 1s→2s→2p→3s→3p→4s→3d1s→2s→2p→3s→3p→4s→3d, according to the following graphic,…
How are the electrons distributed in an atom? You might recall from your general chemistry course that, according to the quantum mechanical model, the behavior of a specific electron in an atom can be described by a mathematical expression called a wave…
As you might remember from your general chemistry course, an atom consists of a dense, positively charged nucleus surrounded at a relatively large distance by negatively charged electrons (Figure 1.3). The nucleus consists of subatomic particles called neutrons, which are electrically…
Figure 1.1 The enzyme HMG–CoA reductase, shown here as a so-called ribbon model, catalyzes a crucial step in the body’s synthesis of cholesterol. Understanding how this enzyme functions has led to the development of drugs credited with saving millions of lives. (credit: image…
Erik Erikson Erik Erikson proposed the psychosocial theory of development. In each stage of Erikson’s theory, there is a psychosocial task that we must master in order to feel a sense of competence. Erikson proposed that we are motivated by a…
In addition, articles comparing life expectancy of athletes compared to that of nonathletes were reviewed. Results of 13 studies describing eight different cohorts suggest that regular physical activity is associated with an increase of life expectancy by 0.4 to 6.9 years.
Glass sponges are considered the oldest animals on Earth—and it’s by a long shot. Scientists estimate that they can live for more than 10,000 years, possibly 15,000 years maximum. One glass sponge observed by researchers in the Ross Sea, a bay…
life span, the period of time between the birth and death of an organism. It is a commonplace that all organisms die. Some die after only a brief existence, like that of the mayfly, whose adult life burns out in a…
Lifespan development explores how we change and grow from conception to death. This field of psychology is studied by developmental psychologists. They view development as a lifelong process that can be studied scientifically across three developmental domains: physical, cognitive development, and…
Common benefits include the following: To gain a better understanding of one’s own life experiences. This can help people personally reach an understanding of what childhood events shaped their adulthood. To gain knowledge of how social context impacts development.