eLECTRON CONFIGURATION!!!?

Question

please explain how to find out how many elememts are there in each period.any law?
I read that the number of elements is equal to the energy level of that period.HOW?

Answer 1

Here is the rough picture:
The energy of the electron configuration about the nucleus depends on how the electrons are placed in the allowed orbits around the nucleus. "Allowed" orbits?? Yes: in quantum mechanics, only certain kinds of orbits are allowed. This is very different from the case of, say, satellites orbiting the earth, where the orbit can change smoothly from one kind to the next.

So there is a set of allowed orbits, and the shape of the orbit determines its energy. Atoms try to stay in the lowest energy configuration, and they must be electrically neutral, so the orbits are filled according to increasing energy level as protons are added to the nucleus. Therefore the atomic number determines the number of electrons. Only one electron is allowed per orbit, and the orbits can be classified by shape.

The orbit energies roughly jump in periods. The lengths of these periods are the lengths of the rows in the periodic table. The first period has only two orbits, so only two elements are in it: Hydrogen and Helium. The next two periods have 8 orbits, so eight elements each, but the next has 18. For a while people thought there were 8's from then on, but then they realized that many of the elements that were chemically very similar (like Iron, Cobalt, Vanadium...) were actually different in subtle ways. The rule of 8's works if you ignore the big chunk in the middle of the table. The reason is that there are some inner orbitals which contribute less to the chemical properties but which it is energetically cheaper to fill.

You start getting longer periods when these inner orbitals start to fill up, and so you get bunches of elements which have similar chemical behaviors but with different atomic numbers.
These are called "transitions" in the "normal" 8 element period. It is as if more room was found in a crowded city for a few more tenants. These orbits are stuck in below the chemically active outermost shell.

A good periodic table will let you read off the electron configuration for each element. The kinds of orbital are labelled by letters. They go: s,p,d,f,g.... The "energy shell" where these orbitals live is numbered. Finally the numbers of electrons in each kind of orbital is also a number. So Hydrogen has 1s1. Reading right to left, this is "one electron in the s-type of the first shell." Oxygen is 1s2 2s2 2p4 or "4 electrons in the p-type of the second shell, 2 electrons in the s-type of the second shell, 2 electrons in the s-type of the second shell."

A good book on this is "The Periodic Kingdom" by PW Atkins.

Answer 2

The simple calculations have shown that there are as many number of elements in a period as it can hold the number of electrons like 1st pd can hold 2 electrons so teher are 2 elements similarly 2nd pd can hold 8 electrons so there are 8 elements and so on.

Answer 3

simple formula to calculate how many are the most electrons on the last layer, which leads to how many are the most elements in each period:
electrons=2n^2, n-the number of the period from which is the element
but of course you must not forget that in the outside layer of electrons can be hold only 8 electrons

Answer 4

No laws....go to a periodic table and count. Although you can start at the first period....each eelement (H2, Li, Na etc) have one electron, (Mg, Ca etc) have two. Skip the transitions and you get 3,4,5,6,7,and 8 in the respective columns.

Answer 5

there are no laws to find the no of elements in periods they differ
these elements usually are segregated by outer configuration into groups.but however ther are 1st period =very short period=2 elements
1st short period=8(li--ne)
2nd short p na--ar=8elements
1st long period =18
2nd long period =18
ist very long period =32
incomplete period........
given by neil's bhor

Answer 6

periodic table is based upon the group like1st group elements 2Nd group elements and so on ...u have to learn the name of elements depending upon group..it depends on number of electrons present in sub-Shell,sub-shells are S,P,D,F THEIR U HAVE DIFFERENT SHAPES AND THEY CLASSIFIED INTO DX,DY,DZ..FX,FY,FZ

Answer 7

lol....sorry .read long ago(around 4 months before)...lol