Shell, electron outermost

In general, we can think of an atom of any element as having a noble-gas core surrounded by a number of electrons in the valence shell, the outermost occupied shell. The valence shell is the occupied shell with the largest value of n. 

Action process - a representation of an unfolding action and event processes of change and transitoiy spatial arrangement (e.g. a diagram showing how a sodium atom becomes a sodium atom through the loss of the outermost shell electron). 

Now that we know how to determine hybridization states, we need to know the geometry of each of the three hybridization states. One simple theory explains it all. This theory is called the valence shell electron pair repulsion theory (VSEPR). Stated simply, all orbitals containing electrons in the outermost shell (the valence shell) want to get as far apart from each other as possible. This one simple idea is all you need to predict the geometry around an atom. First, let s apply the theory to the three types of hybridized orbitals. 

The first shell of any atom holds a maximum of two electrons, and the second shell holds a maximum of eight. Thus, the first two electrons of potassium fill the first shell, and the next eight fill the second shell. The outermost shell of any atom can hold at most eight electrons. In potassium, there are nine electrons left, which would fit into the third shell if it were not the outermost shell. However, if we put the nine electrons into the third shell, it would be the outermost shell. Therefore, we put 8 of the remaining electrons in that shell. That leaves the one electron left in the fourth shell. 

In forming ions, the transition metals lose their valence (outermost) shell electrons first, followed by their outer d electrons. Note In order for transition metal ions to be colored, the d orbitals must be partially filled. In this case, the solution containing the Ni2+ ion would be colored (green). 

Lithiums outermost electron experiences an effective nuclear charge of+1, while those of neon experience an effective nuclear chatge of +8. As a result, the outer-shell electrons in neon are closer to the nucleus than is the outer-shell electron in lithium, and so the diameter of the neon atom is smaller than the diameter of the lithium atom. 

The effective nuclear charge for an outermost shell electron in fluorine is 9 — 2 = 7. The effective nuclear charge for an outermost shell electron in sulfur is 16 - 10 = 6. 

The electrons in the outermost shell of the structure of an atom. Since these electrons are commonly the means by which the atom enters into chemical combinations—either by giving them up. or by adding others to their shell, or by sharing electrons in this shell—these outermost electrons arc called valence electrons. 

All atoms contain a centrally located nucleus composed of a mixture of protons and neutrons (except for the hydrogen nucleus, which contains only a single proton). Electrons surround the nucleus in a series of shells. Electrons in the innermost shell are the hardest ones to remove from the atom, and electrons in the outermost shell are the easiest to remove. The outermost shell is called the valence shell because, in most chemical reactions between atoms, electrons are either added to or removed from this shell. 

There is one other unusual thing about the transition metals, and it involves their valence shell electrons. Unlike most elements, the valence electrons of transition metals are not in their outermost electron shell, but from their next-to-outermost shell. The valence electrons move through the d orbital in this shell, making the transition metals the d block of the periodic table. 

Before looking at molecules, we need to review the structure of atoms. Most of the mass of an atom is concentrated in the nucleus. The nucleus consists of protons, which are positively charged, and neutrons, which are neutral. To counterbalance the charge on the nucleus due to the positive protons, the atom has an equal number of negative electrons in shells or orbitals around the nucleus. Because the electrons in the outermost electron shell (the valence electrons) control how the atom bonds, atoms are often represented by their respective atomic symbol surrounded by dots representing the outer-shell electrons. Such representations for some of the elements of interest to us are shown in Figure 1.1. The number of electrons in the valence shell of an atom is the same as the group number of that atom in the periodic table. 

The terms oxidation and reduction with respect to chemical processes in soil-water systems refers to potential electron-transfer processes. Under oxidation, a chemical element or molecular species donates electrons (e ), whereas under reduction a chemical element or molecular species accepts electrons. The potential of an atom of any given element to react depends on the affinity of its nucleus for electrons and the strong tendency of the atom to gain maximum stability by filling its outer electron shell or comply with the octet rule. The octet rule states that to gain maximum stability an atom must have eight electrons in its outer shell or outermost energy level. 

The nuclear charge experienced by the outermost electrons of an atom the actual nuclear charge minus the effects of shielding due to inner-shell electrons. Example Set of dx2-y2 and dz2 orbitals those d orbitals within a set with lobes directed along the x-, y-, and z-axes. 

To represent the formation of bonds between atoms, it is convenient to use a system known as electron dot notation. In this notation, the symbol for an element is used to represent the nucleus of an atom of the element plus all the electrons except those in the outermost (valence) shell. The outermost electrons are represented by dots (or tiny circles or crosses). For example, the dot notations for the first 10 elements in the periodic table are as follows ... 

Under normal conditions, a chemical reaction involves the electrons occupying the outermost shells, or valence shells, of the atoms involved. Hence the chemical properties of an atom arise from its tendency to lose electrons from, or to attract electrons to, its valence shell. This tendency will depend upon the electronic structure of the atom and the nuclear charge experienced by the valence shell electrons. Thus, in order to explain the chemistry of a transition element, it is first necessary to consider its atomic structure and how this influences the binding of its valence shell electrons. 

Chemical bonding usually involves only the outermost electrons of atoms, also called valence electrons. In Lewis dot representations, only the electrons in the outermost occupied r and p orbitals are shown as dots. Paired and unpaired electrons are also indicated. Table 7-1 shows Lewis dot formulas for the representative elements. All elements in a given group have the same outer-shell electron configuration. It is somewhat arbitrary on which side of the atom symbol we write the electron dots. We do, however, represent an electron pair as a pair of dots and an unpaired electron as a single dot. 

Valence shell The outermost occupied electron shell of an atom. 

Electrons in the outermost shell are called valence shell electrons. For example, the electron configuration of Se is [Ar]4s23c/ °4p, and its valence shell electron configuration is 4sMp. ... 

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