10/31/11
Post date: Nov 01, 2011 4:3:15 PM
Bell ringer (verbal): atoms can get to a stable number of electrons either by transferring electrons or by ____________________ electrons.
Intro to covalent bonds notes
Covalent bonds occur when atoms share electrons, and the atoms must stay close in order to continue sharing
Covalent bonds only exist between elements on the right side of the table (and also Hydrogen), which are all atoms that are close to having a full outer shell of electrons
Covalent bonds are weaker than ionic bonds. While ionic compounds are always solids at room temperature (due to their strong bonds), covalent compounds can be solid, liquid, or gas at room temperature.
Modeling covalent bonds examples
Chlorine bonding with itself
Chlorine is in the 7th column, and so has 7 valence electrons
In order to reach a stable number of electrons (8), each chlorine will put one electron in the middle and will share with the other Chlorine atom
To show that these two atoms are now connected, we draw that pair of shared electrons as a line going between the two atoms, and refer to it as a bond
Oxygen bonding with itself
Oxygen is in the 6th column, and so has 6 valence electrons
In order to reach 8 valence electrons, oxygen needs 2 more electrons. To accomplish this, two oxygen atoms will pair up and each share 2 electrons with each other
We replace each pair of shared electrons with a line to show a bond
When oxygen bonds with itself, it forms double bonds, which are stronger than the single bonds formed in the previous example
Assignment: intro to covalent bonds
For each of the pairs of elements below, draw a model and write the formula for the compound they form.