BONDING VIDEOS AND ANIMATIONS

Before the Bell Rings… Grab a note sheet off

the center stool Get out your

Periodic Table. Fill in the first FIVE

questions

Intro to Bonding Video Check your answers and then answer the

rest of the questions based on this video. Intro to Ionic/Covalent Video

What do atoms do to get happy?

What is the “goal” of atoms? What makes them happy? To achieve a filled valence shell.

How can atoms achieve this? To do this, atoms must gain or lose electrons to

form ions. Or others share electrons. ( both are forms of bonding)

So what do atoms do to bond?They make an Ion-

• Atom that has gained or lost an electron, and therefore has a positive or negative charge based on the number of electrons it has lost.

What are 2 Types of Ions?Cation- positively charged

ionAnion- negatively charge

ion

Ionic Bonding What is an Ionic

Bond? Complete transfer

of 1 or more electrons from one atom to another (one loses, the other gains) forming oppositely charged ions that attract one another

Good Animation on Ionic Bonding

Covalent Bonding?

What is a Covalent Bond

Some valence electrons are shared between atoms to achieve a “full” valence shell.

Covalent Bond FormationA bond can result from an overlap of atomic

orbitals on neighboring atoms (sharing of electrons in those orbitals).

Note that each atom has a single, unpaired electron.

ClH H Cl••

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+

Overlap of H (1s) and Cl (3p)

Review of Valence Electrons

Remember that valence electrons are the electrons in the OUTERMOST energy level.

We know this by looking at the groups on the Periodic Table.

So how can we write out a compound that is bonded?

2 Methods: Draw up the Lewis Dot Structures. Swap Charges (works only for ionic) How to Make Ionic Bonds

Lewis Dot Structure Step 1, determine the # of

valence electrons (either through group # for first 18 or through looking at electron configuration) If you can lose them, then you get

a + charge. Why? If you need them, you get a (-)

charge. Why? Step 2, Then write the Atomic

Symbol, surrounded by the electrons represented as dots.

Lewis Dot Structure Con’t Step 3, place the dot structures next to

each other (metal first if ionic bond). Then exchange dots.

Switch the Charges Method

Write each of the atoms with their charges.

Then swap the charges down to the front of the other atom to determine how many you need of each to balance out the charges.

What do the numbers mean in a chemical formula?

Subscripts determine the number of atoms of that element in the molecule.

Coefficients determine how many molecules you have.

Let’s Practice