why some elements have different valences?

Question

why they don't represent the same valence?

such as: Fe has +2, +3...

Answer 1

because every element has unique identity... their valence represents how stable are them...

Answer 2

Electrons seek the lowest level of energy as their best stability level. When electrons leave to create ions, it is based on the stability being achieved. Elements in the "d" block are called transition elements becuase their d orbital electrons can get involved in valences.

Although the "d' orbitals can hold 10 electrons, there is a minor level of stabilitiy when they hold 5 electrons, i.e. one electron ineach orbital. This means that a transition element can have a normal valence when the "s" and "p" electrons leave and other valences when some of the "d" electrons leave as well.

Take iron, Fe, as an example. It can have a valence of 2 when the 'S'" electrons leave, and it can have a valence of 3 when one of the "d" electrons leaves as well, creating a stability level with 5 "d" electrons.

Answer 3

Valences are based on the number of electrons in the outer shell. Metals are known to be multivalent. It is possible for an element to have differing amounts of electrons as the proton and neutrons are viewed as the nucleus of the atom and do not vary (neutrons can - see deuterium) as often as electrons.

Electrons, in relative terms, easily move from atom to atom or create the bonds in molecules.

At one company where I worked, we intentionally 'reduced' iron in a hydrogen/nitrogen atmosphere at temperature. The reduced iron held magnetic charges better and had more desirable performance characteristics.