Electronegativity - bond polarity

What is used to measure electronegativity?

Pauling scale (0-4)

What does electronegativity depend on? (3)

• The nuclear charge.

• The distance between the nucleus and the outer shell electrons.

• The shielding of the nuclear charge by electrons in inner shells

Why is electronegativity greater if the atom is smaller?

Because the nucleus is closer to the shared outer main level electrons

How does electronegativity change going across a period and why?

Increases because the nuclear charge increases, the number of principle energy levels remain the same and the atoms become smaller.

What is polarity?

The unequal sharing of electrons between atoms that are bonded covalently

What is electronegativity?

The ability of an atom to attract electrons in a covalent bond

How is electronegativity affected if the nuclear charge is larger?

Electronegativity is greater

How does electronegativity change going down a group and why?

Decreases because there is more shielding by electrons as the atomic radii increases

Where are the most electronegative atoms found on the perodic table?

At the top right hand corner of the periodic table, ignoring noble gases.

Which are the most electronegative atoms?

Flourine (4.0), oxygen (3.4), chlorine (3.2) and nitrogen (3.0)

Electron diagram of fluorine molecule

Electron cloud around fluorine molecule

Even bubbles around both atoms

Is the covalent bond between fluorine molecules polar or non-polar?

Non-polar

Are C-H bonds polar or non-polar and why?

Non-polar because atoms have very similar electronegativities

Electorn diagram of hydrogen fluoride

Electron cloud of hydrogen fluoride