4.1.1.7 Electronic structure

How are atoms become stable?

Having a full outer shell or reacting with another element to gain or lose an electron

How do we know the number of electrons in an atom?

The number of electrons is equal to the number of protons so look at their atomic number

How are electrons are arranged

In shells around the nucleus

First one to fill is the one closest to the nucleus- this one has the lowest energy level

How many electrons can shells hold?

1st- 2 electrons

2,3,4….- up to 8 electrons

Unstable

Wants to react with another atom, so it can have a full outer shell

Electronic​ ​structure​ ​of​ ​an​ ​atom​ ​tells​ ​you

Na-11

​ ​how​ ​many​ ​electrons​ ​are​ ​in​ ​each​ ​shell e.g.​ ​for​ ​sodium:​ ​2​ ​electrons​ ​in​ ​shell​ ​1​ ​(closest​ ​to​ ​nucleus),​ ​8​ ​in​ ​shell​ ​2,​ ​1​ ​in​ ​shell​ ​3 Electronic​ ​structure=​ ​2,8,1​