Student Exploration: Polarity and Intermolecular Forces

Vocabulary: dipole, dipole-dipole force, dipole-induced dipole force, electronegativity,

intermolecular force, ionic bond, London dispersion force, molecule, nonpolar, nonpolar

covalent bond, partial charges, polar, polar covalent bond, valence electron

Prior Knowledge Questions (Do these BEFORE

using the Gizmo.)

1. A big bully is having a tug-of-war with a small child.

There is a ball attached to the middle of the rope.

Toward whom will the ball move? (1)The big bully

2. Two equally strong kids are having a tug-of-war. What do you expect to happen to the ball in

this situation? (1) I expect the ball to not move and just stay in the middle

Gizmo Warm-up

Just like in a tug-of-war, atoms that are bonded to one another pull

on the electrons they share. In the Polarity and Intermolecular

Forces Gizmo, you will explore how these opposing forces relate to

bond types and the forces between molecules.

To begin, drag the Na (sodium) and Cl (chlorine) atoms into the simulation area. Turn on Show

valence electrons. A valence electron is found in the outermost energy level of the atom.

1. Click Play ( ). What do you notice? (1) The chlorine atom takes the valence electron from

the sodium atom.

2. Which atom seems to be pulling more on sodium’s one valence electron? (sodium or

chlorine) (1) chlorine

How do you know? (1)I know because the valence electron is now in chlorines valence shell

since it pulled the electron more than the sodium did, it now has a more negative charge.

3. What happens to the colors of the simulated atoms, and what does this indicate? (1) The

sodium atom turned blue which indicates a positive charge and the chlorine atom turned red

which indicates a negative charge.

Drag the atoms/molecule down to the bottom to remove them from the simulation area.

Comment [1]: chlorine becomes bigger,

sodium smaller minus 0.5

2019

Activity A:

Bond polarity

Get the Gizmo ready:

● On the BOND POLARITY tab, click Reset ( ).

● Drag the atoms out of the simulation area.

Introduction: A neutral atom has the same number of protons as electrons. Atoms that gain

electrons become negatively charged, while those that lose electrons become positive. A polar

bond forms when shared electrons are pulled closer to one atom than another, causing the

bonded atoms to become partially charged. In a nonpolar bond, electrons are shared equally.