Unit 1: Matter Bonding Mr. Le Fall 2018

Why bond!? Atoms are usually unhappy and crazy! They need to bond to calm down and become stable

Why bond!? To become stable, atoms will bond with other atoms, so that both atoms will: Have 8 valence electrons or Have a full outermost energy level

Valence Electrons Valence Electrons: electrons on the last energy level. Atoms can not have more than 8 valence electrons.

Energy Levels Each energy level can only hold a specific number of electrons until it is “full”. Energy level 1 = 2 valence electrons Energy level 2 = 8 valence electrons Energy level 3 = 18 valence electrons Energy level 4 = 32 valence electrons Use 2n2 to predict how many can fit on each energy level

What patterns do you see between your diagram of the atom and the atom’s location on the periodic table?

Unit 1: Matter Molecules vs Compounds Mr. Le Fall 2018

Molecules Molecule: particles that form when at least 2 atoms bond. If you have at least 2 atoms bonded, you have a molecule. These can be the same atoms bonded together or different atoms bonded together.

Compounds Compounds: particles that form when two or more different elements bond. You need to have at least 2 different atoms bonded to have a compound. There has to be different atoms bonded together.

Compounds Compounds are usually different from the elements that form them. Sodium + Chlorine = Salt (Sodium Chloride)

Remember!!! All compounds can be molecules, but not every molecule can be a compound. For a substance to be a molecule, it needs to have at least 2 atoms bonded. For a substance to be a compound, it needs to have at least 2 different atoms bonded.

Chemical Bonds During bonding, atoms will either share their valence electrons or transfer their valence electrons

Ionic Bonding Ionic bond: a chemical bond that forms when atoms transfer electrons. An atom loses an electron, while another atom gains an electron. As a result, the atom became an ion.

Ion Ion: a charged atom due to losing or gaining an electron. Example: Fe+2, C-1, Na+1 If an atom loses an electron, what charge does it have? What if the atom gains an electron?

Covalent Bonds Covalent Bonds: a chemical bond that forms when atoms share electrons. As a result, the atoms form a neutral particle called a molecule.

Unit 1: Matter Chemical Formula Mr. Le Fall 2018

Chemical Formula Chemical Formula: A combination of atomic symbols and numbers use to represent atoms that bonded.

Reading Chemical Formulas Chemical Formula for Water is H2O The atomic symbols tells you the names of the elements. The small number behind an element tells you how many atoms it has. If there are no number behind an element, it means one.

Reading Chemical Formulas 2H2O If there is a coefficient in front of the formula, you multiply the coefficient with all the elements in the formula. Similar to the distributive property in math. (Al2O3)2 If there is a subscript after a parenthesis, you multiply the subscript with all the elements in the parenthesis. Similar to the distributive property in math.