Valence electrons?

Question

Does anyone know any helpful tricks in knowing how many valence electrons a given element has?

Answer 1

For the main group elements, the number of valence electrons is the SAME as the group number/column number

Group 1: a ll have 1 valence electron (H group)
Group 2: all have 2 valence electrons (Be)
Group 3: all have 3 valence electrons (B)
Group 4: all have 4 valence electrons (C)
Group 5: all have 5 valence electrons (N)
Group 6: all have 6 valence electrons (O)
Group 7: all have 7 valence electrons (F)
Group 8: except He, all have 8 valence electrons (Ne)

The valence electrons can be seen by writing out hte electron configurations. Transition metals are a little more difficult to simply classify. You must learn their oxidation states and learn their electrons configurations.

Answer 2

If you can see it on a periodic table, you can find out easily, but without one of those, you just have to know how many electrons it has.

The number of electrons in shells is 2, 8, 8, 8...

so if an atom has 15 electrons, you subtract 2, and then 8, until you can't subtract 8 anymore. and you get 5. 5 electrons in the outmost shell.

Answer 3

There is no magic way. You have to memorize the valences, oxidation numbers of the elements,. Afterwards, you can look at the periodic table and reason out why they are. But there is no substitute for the hard work of learning the material.

Answer 4

it requires a periodic table, but, farthest to the left,

the groups, or columns(up and down),

each have a number, thats how many valence electrons there are. easy trick my science teacher taught me.

Answer 5

No trick, just check out the group of the periodic table they are in.