Are molecules and compounds the same thing?

Is this an Element? Yes!

Give 5 examples of molecules that you know. Use the periodic table to look at which atoms are involved in the molecules you listed. – What group or family are the atoms in each molecule coming from? – Are these atoms metals or non-metals? Can you identify a pattern?

Why do atoms form molecules? Atoms want to be as noble as the NOBLE GASES! What is so special? The Noble gases are very stable and they have 8 valence electrons.

Do Noble Gases form Molecules? The valence shell is complete. These atoms do not combine with any other atom to form molecules.

Beg, Borrow and Steal! Atoms will do anything to look like a noble gas. How do we know what atoms will do?

A look at Na and Cl

How do we know what atoms will do?

Take a look at the Lewis Dot Notations Element LiBeBCNF Original Valence Structure Ionic Valence structure

Summary Atoms will share, borrow, steal and lose valence electrons to be more like a noble gas. The goal is to have 8 valence electrons, this is called the octet rule. The number of valence electrons the atom begins with will determine whether it will gain or lose its electrons.

Try it for yourself! How are the following molecules formed? LiBr: MgO: MgCl 2 :

What about atoms like… H Be B These elements are happy to only fill their first orbit (n =1) And so, these kinds of atoms follow the duet rule (want to attain 2 valence electrons)

Try it for yourself! How is following molecule formed? 1.H 2

Ions Ions are atoms that have become electrically charged by losing or gaining electrons.

What is the charge? How can you figure it out? Use the following formula: PROTONS - ELECTRONS = IONIC CHARGE

Types of Chemical Bonds Ionic bonding: the result of electron transfer. Covalent bonding: the result of electron sharing. Hydrogen does not form ionic bonds.

How is following molecule formed? 1.H 2 WHAT TYPE OF BOND IS THIS? covalent

Ionic Bonds The Criss-Cross Rule MgCl or MgCl 2 How do we know? THIS ONLY WORKS WITH IONIC BONDS

LET’S LOOK AT WATER AGAIN Does it smell of anything? Does it conduct electricity? IonicCovalent

POLARITY Polarity exists in a molecule when there is an electrostatic attraction in a molecule. (Unequal sharing of electrons). Oxygen is pulling the oxygen in closer to its nucleus. (unequal sharing of electrons)

Conclusion Hydrogen is a freak!!!! It is a non-metal that got lost on its way to the right side of the periodic table. H is a non-metal!

Well what about HCl? HCl is actually a gas (only an acid in water). HCl(g) vs. HCl (aq). Electrons are equally shared in a molecule of H 2 but not in HCl.

GAS Aqueous Solution Polar molecules, like ionic compounds dissociate or separate in solution. (Form ions)