Mg (magnesium)
Ar
Mg (magnesium)
Potassium
This sounds to me like the definition of an element.
The element with chemical properties most like silicon is germanium. As an example, both are used in semiconductors.
Ar
Mg (magnesium)
Mg
Mg (magnesium)
Fluorine.
Mg (magnesium)
its ion and atom properties differences is atom is like science ion-chemistry
Potassium
Those elements that are also is group II of the Periodic Table, namely Be, Mg, Sr, Ba and Ra.
A physical change changes the physical properties of an element like color where chemical changes change the chemical properties of an element and usually can't be undone.
Physical and chemical properties of an element are things about the element. if its a liquid, solid, gas. what the pH is. what the atomic number and mass is..... stuff like that.
This sounds to me like the definition of an element.