Atoms, their properties and how they are bonded together

Understandings

● A covalent bond is formed by the electrostatic attraction between a shared pair of electrons and
the positively charged nuclei.
● Single, double, and triple covalent bonds involve one, two, and three shared pairs of electrons
respectively.
● Bond length decreases and bond strength increases as the number of shared electrons increases.
● Bond polarity results from the difference in electronegativities of the bonded atoms.
Guidance
Bond polarity can be shown either with partial charges, dipoles, or vectors.

Applications and skills

● Deduction of the polar nature of a covalent bond from electronegativity values.
Guidance
Electronegativity values are given in section 8 of the data booklet.

Bonding overview

Bonding by Magnus Drechsler

Summary of Covalent bonds

Task:
1. Watch the video and take notes
2. Complete the exercises in the video

Lewis dot structure/ Dot and Cross Diagram

Task:

Watch the first video and take notes
Work out as many rules as you can when drawing molecular covalent compounds using lewis structure

Examples/help:

Carbon always forms ? bonds and therefore has ? bonding pairs of electrons
Nitrogen likes to have ? bonds and ? lone pairs
Oxygen likes to have ? bonds and ? lone pairs

Complete the exercises at the end of the video
Draw the lewis dot structure of the following molecules:

Molecules:

CL2
O2
N2
C2H4
CO2
CN-
NH4+
H3O+

Choose one of the molecules to explain how to draw the lewis structure:

Use visuals and drawings in your explanation
Record your explanation
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Peer assess 2 classmates videos

The second video is explaining the basic dot and cross diagram that you would have used in MYP. This should help you to refresh your memory if you need to.