Valence electrons increase in number on moving from left to right on the Periodic Table.
another question might be
it increases the amount of valence electrons.
As the atomic number increases from left to right in a specific period so the number of valence electrons also increase.
The "d" block elements have electrons in a "d" in a lower shell than the valence electrons in the "s" orbital. These "d" electrons can be moved to the outer shell to give a metal a higher valence then the value of 2 that might otherwise be expected. Osmium can have a valence as high as 8. Additionally, the outer shell electrons can be moved from the "s" orbital down to the "d" orbital to give a metal a lower valence, perhaps the most notable case of this is silver which almost always forms a 1+ ion rather than 2+.
Assuming you are talking about the electrons in their shells (not the displaced ones):It depends on the distance of those electrons from the nucleus. For example electron in the outer shell of potassium (K) is further away form the nucleus than electron in the outer shell of sodium (Na).It means that potassium can lose this electron in outer shell easier than sodium does, and therefore is more reactive than sodium.
Electrons are negatively charged. Opposites attract, so they are attracted to positively charged bodies.
the electrons in the wire begin to flow
Rubber is what is known as an electrical insulator. The difference between insulators, which block the flow of electricity, and conductors, which permit the flow of electricity, lies in the availability of mobile electrons in the material in question. Electricity is composed of moving electrons. Some materials, such as metals, contain electrons that are easily moved, hence electric currents move easily in those materials. If a material does not have electrons that are easily moved, then it resists the flow of electrons.
The "d" block elements have electrons in a "d" in a lower shell than the valence electrons in the "s" orbital. These "d" electrons can be moved to the outer shell to give a metal a higher valence then the value of 2 that might otherwise be expected. Osmium can have a valence as high as 8. Additionally, the outer shell electrons can be moved from the "s" orbital down to the "d" orbital to give a metal a lower valence, perhaps the most notable case of this is silver which almost always forms a 1+ ion rather than 2+.
In an intrinsic semiconductor, a few electrons get thermally excited and break from their valence bond to become a free electron. This leaves behind a vacancy in its place called 'hole'. In a P-type semiconductor, B with 3 electrons replaces a Si atom with 4 electrons in the lattice. 3 covalent bonds are formed by B with 3 neighbouring Si. But there is a deficiency of one electron in B for bonding with the 4th Si. This deficiency/vacancy is called a hole. When an electric potential difference is present, the electrons from adjacent valence bond moves into the vacancy near it while moving along the potential. The following represents the movement of valence electron. Terminology: * represents valence electron _ represents hole A is -ve and B is +ve. ..I A * * * _ * * * B .II A * * _ * * * * B III A * _ * * * * * B .IV A _ * * * * * * B I- Hole is at the 4th position. II- At first, the 3rd electron from left shifts right to fill the vacancy and leaves behind a vacancy in its place. The vacancy is at the 3rd position. III- Next, the 2nd electron from left has shifted to the 3rd place and filled up that vacancy but leaves a vacancy at its place. The vacancy is at 2nd position. IV- Now, the 1st electron from left moves to occupy the vacancy at the 2nd position creating another vacancy in its own place. The vacancy is at 1st position. As the electrons moved right, the vacancy moved left. The vacancy is called a hole (just a shorter name for convenience). The movement of holes is really the movement of electron in the valence band. Therefore, the mobility of a hole is indirectly the mobility of valence electrons. Mobility is the velocity acquired per unit electric field. In the intrinsic and N type semiconductors, many free electrons are present i.e. electrons in conduction band which are free to move in the crystal as against valence electrons which can only move in the lattice points. When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that of valence electron but the mobility is the same, as explained earlier. Even for the same electric field, valence electrons cannot move as freely as the free electrons because its movement is restricted. Therefore, the velocity of valence electrons is less compared to free electrons. In other words, the velocity of holes is less compared to free electrons. This means mobility is also less for a hole compared to free electron. Thus, mobility of a free-electron (often abbreviated as 'electron') is greater than that of a hole (indirectly referring to valence electron).
The Lanthanides and the Actinides have been moved in the periodic table simply to save space. --PainRain
Yes first of all, u know that a atom can have maximum of 2 valence electron or 8electrons right?? so if two atoms which has 1 v. electron bond, its oxidation can be +1 or -1. Also the same thing applies to the 8 valence electron, if there is two '4 v. electroned' atom, it can be +4 or -4.. the oxidation state/number can also change depending on the compound that the element is in..... for example normally oxygen is -2 however in peroxide compounds it is -1
Conductors are materials whose atoms have valence electrons operating in energy levels that permit them (the electrons) to be moved easily. Remember that current flow is like musical chairs. Put an electron in one end of a wire and electrons within the wire shift "over" a spot and an electron leaves the other end. If a wire is made of, say, copper (which is selected primarily for its ability to conduct electricity), valence electrons about the copper atoms in the wire occupy energy bands that permit them to be easily moved and the wire will support current flow.
John Dalton
Ernest Rutherford
Electricity
The electrons on the outer shell
Assuming you are talking about the electrons in their shells (not the displaced ones):It depends on the distance of those electrons from the nucleus. For example electron in the outer shell of potassium (K) is further away form the nucleus than electron in the outer shell of sodium (Na).It means that potassium can lose this electron in outer shell easier than sodium does, and therefore is more reactive than sodium.
Electrons are negatively charged. Opposites attract, so they are attracted to positively charged bodies.
the covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide.