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In an SCR why silicon is used?
Si has highest valence electron .
Are free electron in valence band or conduction band?
In semiconductors free electrons are in conduction bands.
Can you dope a semiconductor with holes instead of electrons?
Doping with Group III elements, which are missing the fourth valence electron, creates "broken bonds" (holes) in the silicon lattice that are free to move. The result is an electrically conductive p-type semiconductor.
Why n type and p type are electrically neutral?
An N-type semiconductor is obtained by carrying out a process of doping, that is, by adding an impurity of valence-five elements to a valence-four semiconductor in order to increase the number of free charge carriers. When the doping material is added, it gives away weakly-bound outer electrons to the semiconductor atoms. This type of doping agent is also known as donor material since it gives away some of its electrons. The purpose of N-type doping is to produce an abundance of mobile or carrier electrons in the material. To help understand how n-type doping is accomplished, consider the case of silicon (Si). Si atoms have four valence electrons, each of which is covalently bonded with each of the four adjacent Si atoms. If an atom with five valence electrons, such as those from group 15 of the periodic table , is incorporated into the crystal lattice in place of a Si atom, then that atom will have four covalent bonds and one unbonded electron. This extra electron is only weakly bound to the atom and can easily be excited into the conduction band. At normal temperatures, virtually all such electrons are excited into the conduction band. Since excitation of these electrons does not result in the formation of a hole, the number of electrons in such a material far exceeds the number of holes. In this case the electrons are the majority carriers and the holes are the minority carriers. Because the five-electron atoms have an extra electron to donate, they are called donor atoms. Note that each movable electron within the semiconductor is never far from an immobile positive dopant ion, and the N-doped material normally has a net electric charge of zero.
What is hole current?
There are two type of carriers in any semiconductor. For a given sample, these carriers have a specific concentration and mobility. The current flow due to the holes carriers in any semiconductor is the hole current.Answer'Holes' are imaginary positive, mobile, charge carriers used as a model to represent the behaviour of electric current in p-type semiconducting material. A 'model' is simply a means of explaining complex behavior in terms of something we can easily understand or picture in our minds. In reality, therefore, holes do not exist, but offer a convenient way of explaining current flow in semiconductors in an understandable way. A 'hole' is simply a vacant position, formally occupied by an electron, rather than a real entity. As electrons move in one direction, relative to those electrons, these imaginary holes behave as though they move in the opposite direction (in rather the same way that scenery seems to be moving backwards when you look from a train whereas, in reality, it's the train that's moving forward!). So, as electrons move from negative to positive, holes appear as though the electrons are actually stationary and it's the holes that are moving from positive to negative.So it's convenient to think of current flow through 'p-type' material, in particular. in terms of imaginary holes moving in the opposite direction to electron flow.(You see a similar effect with led message boards. The message is formed by bright led dots that appear to move in one direction; but you can also argue that the message is formed by the unilluminated leds that appear to move in the opposite direction! You can think of the illuminated leds as electron flow and the unilluminated leds as hole flow.)Diouly-dcp's answerfirst lets look at what is holehole: is when an external voltage source of energy acquire to a piece of silicon or other,it allows the valence electrons to thermally jump from the valence bond to the conduction bond, when they moved, a vacancy is left. this vacancy is called holehole current: another type of current occurs at the valence level where the holes created by the free electron exist. Electrons remaining in the Valence Bond are still attached to their atoms and are not free to move randomly in the crystal structure as are the free electron, however a valence electron can move into a near by whole with little change in it's energy level thus leaving another hole where it came from. effectively the hole has more from one place to another in the crystal structure, this is called hole current.(electrons in the valence bond are moving from one hole to another in the valence bond it self, but not to the conduction bond)
Would it be more difficult to remove an electron from sodium or bromine?
It would be more difficult to remove an electron from bromine than from sodium because bromine's valence electron is farther from the nucleus, experiencing weaker attraction compared to sodium's valence electron, which is closer to the nucleus.
Why does valence electron give up outermost energy easily?
The force of attraction between the atom's nucleus and its valence electrons are the least. Hence valence electrons are lost easily.
What are the electron farthest from the nucleus called?
Electrons farthest from nucleus are valence electrons. They are present in outermost orbit.
Is it easier to remove an electron from the outside shell of a K atom than from the outside shell of a Na atom?
Yes, it is easier to remove an electron from the outside shell of a K atom than from the outside shell of a Na atom. This is because potassium (K) is in Group 1 of the periodic table with one valence electron, which is further away from the nucleus compared to sodium's (Na) single valence electron in Group 2. The electron in the outer shell of potassium experiences less attraction to the nucleus, making it easier to remove.
Why does not the nucleus attract the atoms from top to bottom in a periodic table?
Down a group, the number of shell increases and the electron enters into a different shell. Hence, the distance between the nucleus and valence electron increases and the nuclear attraction decreases
What is electron shielding?
•The shielding effect describes the decrease in attraction between an electron and the nucleus in any atom with more than one electron shell. •It is also referred to as the screening effect or atomic shielding. •Shielding electrons are the electrons in the energy levels between the nucleus and the valence electrons. They are called "shielding" electrons because they "shield" the valence electrons from the force of attraction exerted by the positive charge in the nucleus. Also, it has trends in the Periodic Table
Why is it easier for strontium to lose valence electrons than calcium?
Strontium is larger in size compared to calcium due to more electron shells, making it easier for strontium to lose valence electrons farther from the nucleus. This results in weaker attraction between the valence electrons and the nucleus, leading to easier electron loss in strontium compared to calcium.
What is the valence electrons weakest attraction?
The valence electrons experience the weakest attraction to the nucleus in an atom. This is because they are the outermost electrons and are furthest from the positively charged nucleus, making their attraction relatively weaker compared to the inner electrons.
What is a smaller atomic radius of beryllium be?
A smaller atomic radius for beryllium would result from an increased positive charge in its nucleus, leading to a stronger attraction between the nucleus and the valence electrons. This increased attraction pulls the electron cloud closer to the nucleus, resulting in a smaller atomic radius.
Which valence electron if further from the nucleus rubidium or strontium?
Rubidium has one valence electron in the 5th energy level, while strontium has two valence electrons in the 5th energy level. Since rubidium has only one valence electron compared to strontium's two, the valence electron in rubidium is further from the nucleus. This is due to the increasing number of electron shells as you move down a group in the periodic table.
What are the farthest electrons from the nucleus?
It's called a valence electron.
What are the electrons farthest from the nucleus?
It's called a valence electron.
