# Ionic number

#### kyle_soule

I'm having a terribly difficult time figuring this out and I'm (ashamedly) sure it is quiet simple. How do I know or figure out the ionic charge of a particle. Such as Na or Cl.

How do I know if they are a minus 1 or positve 2 or what they are?

#### Beren

Ah, well, this isn't too difficult.

For non-metallic elements, it's very easy. Noble Gases (the ones farthest to the right), have a charge of 0. Now, as you go to the left, the charge goes down (-1) for every column. Flourine has a charge of -1, Oxygen -2, and so on. When you get to -4, then it's +4/-4. and it starts decreasing as you keep going left. Lithium has a charge of +1 then.

For metallic elements, it gets difficult. There's really only one way to do it, memorize 'em. ;)

Last edited:

#### Zargawee

for metallic elements , you have to know how to distribute electrons on atom's shells.
for exmple Cobalt(27Co] is known as a Metal with two usual ions : +1 , +2 , +3
that's becuase It's electronic distribution gois like this :
27Co = 1s2 2s2 2p6 3s2 3p6 4s2 3d7
as you know , every etom always try to get to the low energy situation , so , it would lose the electrons in the shell with highest energy , which are from the 4th orbit , in 4s2 , and since 3d is almost equal to 4s , so the atom might lose some electrons from it.
Therefore , B family always make +2 ions , beside other ions depending on the atomic number of the element.

also , when you learn how to distribute electrons on atom's shells , this ion things will become very easy for you , so I suggest you learn them .
Excuse my bad enlgish , I tried my best

Last edited by a moderator:

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving