quantum number
The number most usually associated with electrons is minus one, which describes their electrical charge.
Flourine and Cholrine have similar properties because they have the same number of electrons in outmost shell (7). Each group has similar properties because their amount of valence electrons (electrons in the outmost shell) can only support bonding with certain elements.
Because they have gained or lost electrons and are no longer neutral.
Electrons determine the chemical properties of an atom.
Electrons determine the chemical properties.
Elements whose atoms have the same number of outer electrons have similar properties..
Elements whose atoms have the same number of outer electrons have similar properties..
Chemical properties depend on electrons.Isotopes of an element have the same number of electrons and different number of neutrons.So they have similar chemical properties and different physical properties.
valence electrons
Group number describes the number of valence electrons. It helps in estimating chemical properties of that element.For example-group-1 elements have 1 valence electronThe group number of an element is equal to the number of valence electrons. The number of valence electrons is responsible for the chemical properties. So the chemical properties of the element can be determined by the group number.
the number of electrons
This is the number of valence electrons.