The number 8 comes from 4 pairs of electrons, each in an orbital. Atoms with an n=2 valence level have only 1 s and 3 p orbitals, so They can have only 8 electrons. Elements whose valence level is n=3 or higher can form valence states with more than 8 electrons.
Why can an atom only have 8 valence electrons?
Some books and dictionaries define valence electrons as “electrons in the highest principal energy level”. By this definition an element would have only 8 valence electrons because the n−1 d orbitals fill after the n s orbitals, and then the n p orbitals fill.
Is 8 the max number of valence electrons?
Generally, the maximum number of electrons that the outermost shell of an atom can have is 8 ( eight ).
Why are there only 8 electrons in the outer shell?
This is due to the quantum nature of the atoms , where electrons are arranged into shells: there are 2 electrons in the first called the K shell, 8 in the second (L-shell), 18 in the third (M shell). ...
What is the element with 8 electrons?
Oxygen is the eighth element in the periodic table, with the symbol O. This means that it has eight electrons in its neutral state.
Do all ions have 8 valence electrons?
Most atoms do not have eight electrons in their valence electron shell . Some atoms have only a few electrons in their outer shell, while some atoms lack only one or two electrons to have an octet.
What is the maximum valence?
The outermost shell is called valence shell and it can never have more than 8 electrons in any atom.
Why does the third shell have 8 electrons?
The electron capacity of the third shell is 8, when there are no shells above it . And that is the case for all elements in the third period. It is only when there are outer shells surrounding it that the third (or higher) shell has a higher capacity.
What type of element has 8 electrons in their outermost level?
Similarly, neon has a complete outer 2n shell containing eight electrons. These electron configurations make helium and neon very stable.
When atoms have fewer than eight electrons, they tend to react and form more stable compounds . Atoms may lose, gain or share their valence electrons to achieve eight electronic configuration. Thus an atom will continue to form bond until it achieves eight electrons in the outermost shell.
Which of the following has no 8 valence electrons?
Hence, Ca+ does not have eight electrons in its valence shell.
Why is the number of valence electrons present important?
Valence electrons are important, as they indicate an element’s bonding behavior, stability, and reactivity .
Which element rarely reacts because it has 8 electrons in its outer shell?
Noble gases are the least reactive of all elements. That’s because they have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.
Why ions are more stable than atoms?
If the outermost shell of an atom does not complete octet, it is unstable. ... So, atoms exist only in two forms either in the form of molecules or ions. Ions are formed when atoms gain or lose electrons to achieve the electronic configuration of its nearest inert gas . So, ions are more stable than atoms.
Why can sulfur hold more than 8 valence electrons?
To accommodate more than eight electrons, sulfur must be using not only the ns and np valence orbitals but additional orbitals as well. Sulfur has an [Ne]3s 2 3p 4 3d 0 electron configuration, so in principle it could accommodate more than eight valence electrons by using one or more d orbitals .
Which has maximum number of valence electrons?
Hence we can see that phosphorus has the maximum number of valence electrons.
Which of the following has maximum number of valence electrons?
Phosphorus (P) has the maximum number of valence electrons, equal to 5.
Is it 8 or 18 electrons in third shell?
In this sense the third shell can hold 8 electrons. 4s2 not the third shell, but the next 10 electrons go into the 3d orbitals that are part of the third shell but shown on the fourth shell level. ... So the third shell can be considered to hold 8 or 18 electrons but in total the third shell can hold 18 electrons.
Why is 3rd shell 8 or 18?
Each shell can contain only a fixed number of electrons, up to two electrons can hold the first shell, up to eight (2 + 6) electrons can hold the second shell, up to 18 (2 + 6 + 10) can hold the third shell and so on. ...
Do all shells have 8 electrons?
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. ... For an explanation of why electrons exist in these shells see electron configuration.
How does chlorine end up with 8 valence electrons?
Chlorine has seven valence electrons, so if it takes one it will have eight (an octet). Chlorine has the electron configuration of argon when it gains an electron. The octet rule could have been satisfied if chlorine gave up all seven of its valence electrons and sodium took them.
What family has 8 valence electrons?
Noble Gases The Group 18 elements are the noble gases. Atoms of the noble gases have 8 valence electrons, except for helium, which has 2. Atoms with 8 valence electrons (or 2, in the case of helium) are stable. They are unlikely to gain or lose electrons or to share electrons with other atoms.
What is the group that contains 8 electrons in their outer most shell *?
Group 0 elements – helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn) – have full outer shells. (Group 0 is sometimes called Group 8 – all the elements in the group have eight electrons in their outer shell, except for helium which only has two).
Why do atoms gain and lose electrons to have eight electrons in the valence shell quizlet?
Atoms tend to gain or lose electrons to give them the same number of electrons as the nearest noble gas in the periodic table. ... Explanation:Atoms tend to gain or lose electrons to achieve a stable electron configuration in which the valence shells have their full complement of electrons .
Which element may have more than 8 valence electrons when present in a covalent compound?
Sulfur, phosphorus , silicon, and chlorine are common examples of elements that form an expanded octet. Phosphorus pentachloride (PCl 5 ) and sulfur hexafluoride (SF 6 ) are examples of molecules that deviate from the octet rule by having more than 8 electrons around the central atom.
Why does the octet rule not refer to a stable arrangement of 8 valence electrons?
Why does the octet rule not always refer to a stable arrangement of eight valence electrons? ... Diatomic elements have very high electron affinities . Being single atoms, they quickly form bonds with other elements around them. They are relatively stable only when in the diatomic state.
Why inert gases are stable?
They are the most stable due to having the maximum number of valence electrons their outer shell can hold . Therefore, they rarely react with other elements since they are already stable.
Which species has 8 valence electrons in its Lewis symbol?
The Lewis diagram for given ion is: S2− has 8 valence electrons. The Lewis diagram for given ion is: F− has 8 valence electrons.
Which of the following elements does not want to have eight valence electrons?
The two elements that most commonly fail to complete an octet are boron and aluminum ; they both readily form compounds in which they have six valence electrons, rather than the usual eight predicted by the octet rule.
Which noble gas does not have 8 electrons in the highest energy level?
Which noble gas does not have eight electrons in its highest occupied energy level? Helium , because it only has one s sublevel meaning it only has space for two electrons.
What are the 8 noble gases?
noble gas, any of the seven chemical elements that make up Group 18 (VIIIa) of the periodic table. The elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og) .
Why is chlorine much more likely to exist as an anion than sodium?
Chlorine is much more apt to exist as an anion as compared to that of sodium because the anion of chlorine will have 18 electrons and this will complete its octet which will make it more stable .
Why does the number of valence electrons increase across a period?
As you move across a period, the number of valence electrons changes, but the number of inner electrons does not. Therefore, the effective nuclear charge increases , causing the valence electrons to pull inward.
What family has 7 valence electrons?
Any element in the halogen group will have seven valence electrons. These elements include fluorine, chlorine, bromine, iodine, and astatine.
Which is more stable between atom or ion?
Atoms with less than eight electrons tend to satisfy the duet rule, having two electrons in their valence shell. By satisfying the duet rule or the octet rule, ions are more stable. ... Both ions form because the ion is more stable than the atom due to the octet rule.
Why are ions unstable?
An atom can be considered unstable in one of two ways. If it picks up or loses an electron, it becomes electrically charged and highly reactive . Such electrically charged atoms are known as ions. Instability can also occur in the nucleus when the number of protons and neutrons is unbalanced.
Which is more stable cation or anion?
Like cations, anions are frequently unstable species. These species are stabilized by a number of different factors, not unlike cation stability. ... The more polarizable the atom , the more stable the anion. Within a row of the periodic table, the more electronegative an atom, the more stable the anion.
