- Valence Electrons Are
- Valence Electrons Are Shared
- Valence Electrons Are Transferred
- Valence Electrons Are Found Where In An Atom
- Valence Electrons Are Those In The __________ - Answer Out
Key Differences – Valency vs Valence Electrons
Valency electrons and valence electrons are inter-related terms, and the key difference between valency and valence electrons is best explained in their definitions; valence electronsare the electrons in the outermost shell of an element whereas valency electronsare the number of electrons that should be accepted or removed to attain the nearest noble gas configuration. It is the electrons in the outermost shell that usually contribute to form chemical bonds. In some atoms, the number of valence electrons is equal to the number of valency electrons.
Definition of valence electron: a single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom Examples of valence electron in a Sentence. Key Differences – Valency vs Valence Electrons Valency electrons and valence electrons are inter-related terms, and the key difference between valency and valence electrons is best explained in their definitions; valence electrons are the electrons in the outermost shell of an element whereas valency electrons are the number of electrons that should be accepted or removed to attain the. In chemistry and physics, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
What are Valence Electrons?
The number of electrons in the outermost shell of an atom is called “valence electrons”. Because of this reason, the outermost shell of an atom is called “valence shell”. Most of the time, these are the electrons, which take part in chemical bonding. When elements form cations, they remove electrons from the valence shell. The number of valence electrons in an element determines the group in the periodic table.
What are Valency Electrons?
The number of electrons required to gain or lose to fill the outermost shell of an atom is called “valency electrons”. For a particular atom, the number of valency electrons depends on the number of valence electron in the atom. For Sodium, valency is equal to 1, because it removes the last electron in the outermost shell to achieve octet structure of the nearest noble gas.
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What is the difference between Valency and Valence Electrons?
Definition of Valency and Valence Electrons
Valence Electrons: The electrons in the outermost shell of an atom are called “valence electrons”. For “s” and “p” group elements, the number of valence electrons is equal to their group number.
Example
Valency Electrons: The number of electrons that should be accepted or removed to attain the electron configuration of the nearest noble gas is called “valency electrons” or the “valence” of an atom.
In general, for metal elements (elements in group I, II and III), the number of valence electrons is equal to the number of valency electrons; they remove the electrons in the valence shell to achieve the octet structure.
But, non-metal elements accept electrons to achieve the electron configuration of the nearest noble gas. Therefore, the valency of non-metal elements is calculated by subtracting the total valence electrons from 8.
For Chlorine, Number of valency electrons = 8-7 =1
Characteristics of Valency and Valence Electrons
Valency and Valence Electrons of group VIII elements
Valence Electrons: Group VIII elements are the noble gases, and they are chemically stable. Their outer shell is complete, and it contains eight electrons in the outermost shell (except Helium –He); so that group VIII electrons have eight valence electrons.
Valency Electrons: Valency is a measure of the ability to form bonds with other elements or molecules. Noble gases do not accept or remove electrons to achieve the octet rule since they have already completed the last shell. Therefore, the valency of group VII elements equal to zero.
Image Courtesy:
“Electron shell 010 Neon – no label” by commons:User:Pumbaa (original work by commons:User:Greg Robson) – http://commons.wikimedia.org/wiki/Category:Electron_shell_diagrams (corresponding labeled version).(CC BY-SA 2.0 uk) via CommonsRelated posts:
The electrons of an atom are typically divided into two categories: valence and core electrons. Valence electrons occupy the outermost shell or highest energy level of an atom while core electrons are those occupying the innermost shell or lowest energy levels. This difference greatly influences the role of the two types of electrons in a chemical reaction. Generally, valence electrons can participate in the formation of chemical bonding, but core electrons cannot. While core electrons are not involved in bonding, they influence the chemical reactivity of an atom.
The electron configuration of a oxygen atom is
[ce{O}: ,1s^22s^22p^4 label{1}]
which may be shorted
[ce{O}:, [He]2s^2 2p^4 label{2}]
where the ([He]) stands for the configuration of helium ((1s^2)). Similarly, the configuration of calcium with 20 electrons can be written
[ce{Ca}:, [Ar]4s^2 label{3}]
where the ([Ar]) stands for the configuration of argon ((1s^22s^22p^6 3s^2 3p^6)). Electronic configurations that are the same as noble gases are very stable since they have a full octet (except helium with a full 1s orbital).
The (1s) electrons in oxygen do not participate in bonding (i.e., chemistry) and are called core electrons. The valence electrons (i.e., the (2s^22p^4) part) are valence electrons, which do participate in the making and breaking of bonds. Similarly, in calcium (Equation (ref{3})), the electrons in the argon-like closed shell are the core electrons and the the two electrons in the 4s orbital are valence electrons.
Example (PageIndex{1}): Cobalt
What are the core and valence electrons in cobalt?
Solution
Start by writing the electron configuration of cobalt with 27 electrons:
[1s^22s^22p^63s^23p^64s^23d^7 nonumber]
However, argon has the electronic structure (1s^22s^22p^23s^23p^6), so we can rewrite the configuration as
[[Ar]4s^23d^7 nonumber]
Valence Electrons Are
The two electrons in the (4s) orbital and the seven electrons in the (3d) are the valence electrons: all others are core electrons.
The periodicity of valance electrons can be seen in the Periodic Table. Basically, the periodicity is only applied to the main group elements, while in transition metals, rules are complex.
Valence Electrons Are Shared
The core electrons remain the same in the increase of group numbers in the main group elements. On the other hand, the valance electrons increase by one from left to right of a main period, and remain the same down the column of a main group. This evolution gives periodical change in property of a period, and similar chemical property of a group, which is called periodical trend. The number of valence electrons in a main period is the same as its group number. The table below shows this rule clearly.
Under construction
Figure 1: 1A + 2A are metals. 3A to 8A are non-metals.
However, this periodicity cannot be applied to the transition group, which is more complicated than that of the main group. Although the outermost electrons can be easily determined, the apparent valence electrons considered in chemical reactivity are complex and fluctuated. Electrons going into d sublevel can play either a role of valence electrons or shielding electrons. So there is not always a certain number of apparent valence electrons. The number of apparent valence electrons for the first transition metal period is shown in the table below.
Under construction
Figure 2: Valence electrons for transition metals.
Relationship with Chemical Reactivity
Valence Electrons Are Transferred
The chemical reactivity of an atom is mainly determined by valence electrons. Atoms which have a complete shell of valence electrons tend to be chemically inert. Atoms with one or two valence electrons are highly reactive. This phenomenon can be explained by Hund's rule, which states that orbitals that are empty, half-full, or full are more stable than those that are not. For example, Ne is chemically inert because it has two valence electrons that fill its outermost shell which makes it stable compared to atoms such as Al, which has three valence electrons, but its valence electrons does not fill its outermost shell.
Valence Electrons Are Found Where In An Atom
Although core electrons do not take part in chemical bonding, they play a role in determining the chemical reactivity of an atom. This influence is generally due to the effect it has on valence electrons. The effect can be observed from the gradual change of chemical reactivity in a group. As you go down a group, more shells are occupied by electrons, which increases the size of the atom. The more core electron shells an atom has, the larger the size of the atom, and the farther the valence electrons are from the nucleus, thus the valence electrons will experience less effective nuclear charge and will be easily lost. For example, (ce{Na}) and (ce{K}) can both react with water, but K has a more radical reaction because it has more shells of core electrons which makes the valence electron in its outermost orbital much easier to lose than the valence electron of Na.
References
Valence Electrons Are Those In The __________ - Answer Out
- Miessler, Gary L., and Donald A. Tarr. Inorganic Chemistry. Upper Saddle River, NJ: Pearson Prentice Hall, 2010. Print.
- Brown, Ian David. The Chemical Bond in Inorganic Chemistry the Bond Valence Model. Oxford: Oxford UP, 2006. Print.