How do you find the amount of electron shells in an atom?

Answer 1

To find the number of outer electrons in an element, or valence electrons, look on the Periodic Table of Elements. Look at the last number of the electron configuration. An element that has an electron configuration of 2-7 has 7 valence electrons.

Link to a periodic table of elements with electron configuration: http://www.chemicalelements.com/show/electronconfig.html

Answer 2

atomic number Z - valence #

example:

How many inner electrons are in the element Sn?

-> Sn has 50 electrons

4 valance so 50 - 4 = 46 inner e's

Source(s):Yahoo answers & www.kentchemistry.c om

This is generally true but you need to watch for multi valent metals. Since their valence # can change, so can their # of inner electrons. But if you're just looking for the single atom sitting around, the above is correct.

Answer 3

Using the simple Bohr Model we know the number of electrons in each level.

2 8 8 18 18 32 32

The evidence for these figures is based on ionisation energy studies. The model works very well for figuring out the electrons in the outer shell.

Calcium has 20 electrons (and protons). Its electrons would be arranged as 2 8 8 2.

Calcium has 2 electrons in its outer shell.

Fluorine is element 9. Electrons: 2 7. Seven electrons in its outer shell.

Copper is element 29. Electrons: 2 8 8 11.

11 electrons in its outer shell.

There are more complicated models that allow chemists to figure out the orbitals the electrons are in and their energy levels but the Bohr Model is still useful.But it still has exceptions like in the case of chromium and copper where the outer shell contains only one electron each though it appears to be two.So it is better to follow standard format of the electronic configuration which is a bit complex but still is accurate

Answer 4

We are going to use Bromine (Br) as an example throughout this exercise.

First, we must write the electron configuration for Bromine.

Br: 1s2,2s2,2p6,3s2,3p6,4s2,3d10,4p5

How to find the number of valence electrons:

Valence electrons are those involved in forming compounds.

- For main-group elements, the valence electrons are the outer electrons.

- For transition elements, in addition to the outer nselectrons, the (n-1)d electrons are also valence electrons, though metals Fe (Z=26) through Zn (Z=30) may use only a few, if any, of their d electrons in bonding.

Valence Electrons are the number of electrons in the highest n level.

In this instance, the highest n level is 4. So, there are 7 valence electrons.

How to find the number of inner electrons:

Inner electrons are those an atom has in common with the previous noble gas and any completed transition series. They fill all the lower energy levels of an atom.

Inner electrons = Atomic Number - Valence Electrons

From the Periodic Table, we know that the atomic number for Bromine is 35.

35 - 7 = 28 Inner electrons

How to find the number of outer electrons:

Outer electrons are those in the highest energy level (highest n value). They spend most of their time farthest from the nucleus.

- The easiest way to know the outer number of electrons is by the element's group number.

Bromine is in group number 7.

Answer 5

for example cl have 17 electrons , the electron configuration is 1s2 , 2s2 , 2p6 , 3s2 , 3p5 . the highest occupied energy level is 3 (3s2 , 3p5 ) so the inner shell electrons = 10 (2+2+6)

Answer 6

It can be found using the atomic number of the given element.