Sodium is more electropositive than hydrogen although they are in the same group.
Why is the electronegative value of hydrogen greater than sodium (metal)?
Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. It only takes a minute to sign up.Sign up to join this community
Background: Electropositive implies having tendency to lose electrons to form positive ions. Electronegative implies having tendency to gain electrons to form negative ions. Electronegativity is a concept used to describe the tendency of an atom to attract electrons in a covalent bond.
Why is the electronegative value of hydrogen greater than that of sodium?
This is because sodium after losing an electron gets its octet configuration, but a hydrogen atom after losing an electron will not get the configuration of helium but it can get helium configuration if it accepts an extra electron or forms a covalent bond.
So this implies that sodium is more electropositive that hydrogen, even though they belong to same group.
Sometimes "more electronegative" is used to describe higher electronegativity and "more electropositive" is used to describe lower electronegativity. In this sense, elements are less electronegative (or more electropositive) as you go down any group in the periodic table. However, the difference in electronegativity between hydrogen and sodium is exceptionally large, and correlates with the very different chemistry these two elements show.
The elements that can easily lose electrons to form positive ions are called electropositive elements, for example: metals. Electropositivity is the measure of the ability of elements (mainly metals) to donate electrons to form positive ions.
The elements that can easily accept electrons to form negative ions are called electronegative elements, for example: non-metals. Electronegativity is the measure of the ability of elements (mainly non-metals) to attract electrons towards itself.
Further you can sat that Electronegetivity is the property of an atom with in molecule and Electropositivity is the property of an individual atom.
Now coming to your question as hydrogen can get a stable configuration(of helium) by accepting an electron so it will be called an electronegetive element while sodium can get stable configuration(of neon) by losing an electron so it will be called an Electropositive element.
Throughout the periodic table, there are elements within a group that have different electronegativities.
For example, Nitrogen(atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the periodic table. Write the electronic configuration of these two elements. Which of these will be more electronegativity? Why?
You can apply similar logic to your question concerning the electronegativity of hydrogen compared to that of sodium.