5
$\begingroup$

Sodium is more electropositive than hydrogen although they are in the same group.

Why is the electronegative value of hydrogen greater than sodium (metal)?

$\endgroup$
6
$\begingroup$

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.

| improve this answer | |
$\endgroup$
  • $\begingroup$ doesn't electronegativity mean the capacity of an atom to attract a shared pair of electrons towards itself? $\endgroup$ – Amritansh Singhal Sep 18 '16 at 16:30
  • $\begingroup$ @AmritanshSinghal yes $\endgroup$ – JM97 Sep 18 '16 at 23:57
1
$\begingroup$

Because hydrogen is a nonmetal while sodium is a metal and tends to lose electrons because of metallic bonds present. That's why the electropositivity value of sodium is greater than hydrogen.

| improve this answer | |
$\endgroup$
  • $\begingroup$ agree with your $\endgroup$ – Rasheed Khan Sep 18 '16 at 7:55
0
$\begingroup$

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.

| improve this answer | |
$\endgroup$
-1
$\begingroup$

An electropositive element is an element which has a propensity to lose an electron. (e.g. metals in rancidity)

An electronegative element is an element which has a propensity to gain an electron. (e.g. non-metal in oxidation)

| improve this answer | |
$\endgroup$
  • $\begingroup$ The caps is not necessary. You can bold with asterisks *. i.e.: **[bolded text]** $\endgroup$ – A.K. Oct 12 '18 at 14:22
-1
$\begingroup$

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.

| improve this answer | |
$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.