The valency of magnesium is 2, while copper can have valencies of 1 or 2.
Valency Explained
Valency refers to the combining capacity of an element. It indicates the number of chemical bonds an atom of the element can form with other atoms. This is determined by the number of electrons in the outermost shell of the atom (valence electrons) and how readily it can gain, lose, or share electrons to achieve a stable electron configuration.
Magnesium Valency
Magnesium (Mg) is in Group 2 of the periodic table, meaning it has two valence electrons. To achieve a stable octet (8 electrons in its outer shell), magnesium tends to lose these two electrons, forming a Mg2+ ion. Therefore, the valency of magnesium is 2.
Copper Valency
Copper (Cu) is a transition metal, and many transition metals exhibit variable valency. This means they can form ions with different charges. Copper can have a valency of either 1 or 2.
- Copper(I) or Cuprous: In this case, copper loses one electron to form Cu+ ion, exhibiting a valency of 1.
- Copper(II) or Cupric: In this case, copper loses two electrons to form Cu2+ ion, exhibiting a valency of 2.
The specific valency copper exhibits in a compound depends on the other elements present and the reaction conditions.
