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that's not a proper question i guess..
it's an obvious thing that it's having less energy that's why it's lower energy level while 3d is having more energy than 4s.
Don't go on the numbers 3 and 4. you might be thinkning 3 comes before 4 so 3 should be filled firstly but it's not like that.........
we follow here Aufbau priniple which state that shell having less energy will be filled firstly will electron and then electrons will enter in the higher energy orbit......
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoThey aren't. What you probably mean to ask is why are 5d orbitals filled before 4f orbitals, and the reason is despite the numbers, electrons always occupy the level that requires the least-energy first, as stated in the aufbau principle. In this case, the 5d orbtial requires less energy than the 4f orbital, so it is filled before the 4f orbital. The same can be said for the reason why 4s orbitals are filled before 3d orbitals, which may be what you were asking about.
Wiki User
∙ 10y agoThe reason why the energy of 4s is less than 3d in a multielectron atom of irons has to do with the distance from the nucleus. The closer they are to the nucleus, then the more electron density they will have.
Wiki User
∙ 7y agoI'm not sure I can give you a better answer than "because that's how reality works." There's not some deep secret here ... it's just the way things are. It all makes sense according to the math, but the math is a little complicated, and rather than try to represent it here I will just suggest you find any good book on quantum mechanics (Levine's Quantum Chemistry is my go-to reference) and try to follow along.
If it helps any, the energy difference between s orbitals gets smaller as the principal quantum number increases; the gap between 1s and 2s is bigger than the gap between 2s and 3s which is in turn bigger than the gap between 3s and 4s. The gaps between orbitals within a principal quantum number also get smaller as the principal quantum number gets larger, but there are more of them, so they add up: the gap between 3s and 3p is less than the gap between 3s and 4s, but when you also add in the gap between 3p and 3d the total winds up being more than that between 3s and 4s.
Wiki User
∙ 7y agoThis is true only up until calcium, then from scandium onwards, the 4s is higher in energy than the 3d. The reasons are more complex than easily explained here. It has to do with effective nuclear charge, repulsion of electrons by one another, and a host of other complex factors.
Wiki User
∙ 14y agoits not less energy its actually higher energy..it contains 14 electrons as oposed to 5d (10 electrons)
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What atom is represented in the following orbital diagram 1s2s2p?
The next highest energy electron orbital after 3p is the 4s orbital, after which comes the 3d and then 4p orbitals.
Which orbital should fill first 4s or 3d orbital?
4s will fill first because it is at a lower energy level than the 3d level.
4s orbital is filled before 3d orbital?
The 4s orbital falls in a slightly lower energy level than the 3d orbital when it is empty so it will fill with electrons first, but when it is full of electrons it rises to be above the 3d one so that it will lose electrons first as well.
How would the 4d orbitals differ from the 3d orbitals?
The 4d orbital would be the same shape as the 3d orbital, but just a larger size. Also it would have more nodes than he 3d orbital.
What is the atomic orbital after 4s?
3d
Why does the 4s orbital fills before the 3d orbital?
the 4s orbital is lower in energy than the 3d orbitals
Why are the valence electrons of calcium in the 4s orbital not the 3d orbital?
The 3d sublevel is not filled until after the 4s sublevel, because the 3d sublevel has more energy than the 4s sublevel, and less energy than the 4p sublevel.
Which orbital should fill first 4s or 3d orbital?
4s will fill first because it is at a lower energy level than the 3d level.
What atom is represented in the following orbital diagram 1s2s2p?
The next highest energy electron orbital after 3p is the 4s orbital, after which comes the 3d and then 4p orbitals.
Why do you believe that the valence electrons of calcium and potassium reside in the 4s orbital rather than in the 3d orbital?
The 3d sublevel is not filled until after the 4s sublevel, because the 3d sublevel has more energy than the 4s sublevel, and less energy than the 4p sublevel.
4s orbital is filled before 3d orbital?
The 4s orbital falls in a slightly lower energy level than the 3d orbital when it is empty so it will fill with electrons first, but when it is full of electrons it rises to be above the 3d one so that it will lose electrons first as well.
Why does an electron occupy the 4s orbital before the 3d orbit?
The 3d sublevel is not filled until after the 4s sublevel, because the 3d sublevel has more energy than the 4s sublevel, and less energy than the 4p sublevel.
What is the lowest energy level that can have a d orbital?
3d
What is the lowest energy level that has f orbital?
3 answer for apex
Why do electrons enter the 4s orbital before entering the 3d orbital?
because its energy level is lower
How would the 4d orbitals differ from the 3d orbitals?
The 4d orbital would be the same shape as the 3d orbital, but just a larger size. Also it would have more nodes than he 3d orbital.
Why 4S orbital is filled before 3d orbital during writing electronic configuration Explain with the help of n l rule?
4s-orbital will be filled prior to 3d-orbital.ORBITALnl(n+l)4s404+0 = 43d323+2 = 5Since 4s-orbital has least value of (n+l), therefore ,it will occupy electrons before3d-orbital.The order of increasing of energy of orbitals can be calc. from(n+l) rule or 'Bohr bury rule' According to this rule, the value of n+l is the energy of the orbital and such on orbital will be filled up first. e.g. 4s orbital having lower value of(n+l) has lower energy than 3d orbital and hence 4s orbital is filled up first. For 4s orbital, n+l=4+0=4 For 3d orbital, n+l=3+2=5,therefore 4s orbital will be filled first.
