how to determine electrovalencies from periodic table?

[lacoste]

how do I determine the electrovalencies of elements?

I forgot how to do it by using the periodic table.

just examples: hydrogen's electrovalency is +1

magnesium is 2+

thanks.

[TrueTears]

Magnesium's electron configuration is 2, 8, 2

Therefore it would be likely to lose 2 electrons to become 'stable'. Hence

Is this what you meant?

[lacoste]

sort of,

what if you are given an element with a high atomic number or an element that is unifamiliar?

eg; strontium.


how do i use the periods and groups of the period table to work it out, if thats possible?
[i think theres a way but i forgot]

[TrueTears]

Strontium, Sr will also be 2+ like Mg

Group 1 metals will be 1+, group 2 will be 2+

[Dark Horse]

You can use the Periodic Table to see what the electrovalency is: Look for Strontium on the periodic table, it is in group 2, hence it has an electrovalency of 2. For polyatomic ions (eg. NH4+), you can work out the elecreovalency, but you have to memorise the electrovalencies off a table which will be in your textbook.

[lacoste]

Thanks TT and DarkHorse.

What about elements in group 5 or 6?

What are the charges?

[TrueTears]

3- for group 5

2- for group 6

[lacoste]

3- for group 5

2- for group 6

why?

my memory has gone cold of the periodic table

lol

[TrueTears]

take Nitrogen, N, as example.

electron configuration 2, 5

It needs to gain 3 electrons to have stable configuration. Hence 3-

Same for Oxygen in group 6.

2, 6

It needs to gain 2 electrons to have stable configuration. Hence 2-

[lacoste]

what about the d-blocks?

[chem-nerd]

Most of the d-block (transition metals) will be 2+. Otherwise, you should be able to use your knowledge of the electrovalencies of the ions (simple or polyatomic) that they are bonded with to be able to work out their electrovalency.