Discovering chemistry
Discovering chemistry

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Discovering chemistry

3 Electronegativity

The electronegativity of an element is a measure of the power of its atoms to attract electrons when forming chemical bonds.

The greater the power to attract electrons, the greater the electronegativity.

Let’s look at how this idea applies to chlorine and sodium chloride.

In the Cl2 molecule the two identical atoms have an equal ‘appetite’ for electrons: their electronegativities are equal, so the electron pair is shared equally between them.

But this clearly can’t be the case for sodium chloride.

  • Which atom is the more electronegative, sodium or chlorine?

  • As the chlorine atom is acquiring an electron to form an anion, logically you’d expect chlorine to be the more electronegative.

In fact in sodium chloride, the electron pair has been completely taken over by chlorine, which forms a chloride ion.

DC_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371