# NO WHOT WEEK Warm Up: With your desk partner (1 page for both) 1.On scratch paper, draw an atom, label its parts 2.Then… name 5 physical properties 3.Then.

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NO WHOT WEEK Warm Up: With your desk partner (1 page for both) 1.On scratch paper, draw an atom, label its parts 2.Then… name 5 physical properties 3.Then Turn it in with both names

Element Folder Due Friday at the beginning of class

Rubric! Mostly looks like this

http://www.ptable.com/ Element Square What does it all mean? Atomic Number (# of protons) Average Atomic Mass (# of protons & neutrons added together) Elemental Symbol These are electron orbitals, ignore these numbers

How do we find the number of neutrons in the atom? Steps: 1.Round the atomic mass 2.Subtract the atomic number from that number 3.The difference is the average number of neutrons Atomic Number Average Atomic Mass 56 -26 30

Element Folder: Day 1

Day 2: Element Folder Due Friday at the beginning of class

Warm Up: 1.Look at this Bohr diagrams- which letters are correct? Which are incorrect? 2.The electrons in the outermost energy level are called what?

A Bohr diagram for nitrogen. N Nitrogen 7 14 2 3 1 Mass Number: 4

A Bohr diagram for neutral nitrogen atom. 7 P 7 N

Special Electrons Valence Electrons ◦ In the outermost energy level of an atom ◦ Can bond with other atoms 1 valence e - 7 valence e -

Periodic Table of Bohr Models New energy level for each new row (period) on the table Same number of valence electrons for the atoms in each column (group) Number of valence electrons = periodic column #

Two is cool! Eight is great! Everything wants a sense of fulfillment- even atoms To get this- Take charge! Ions are charged particles due to the gain or loss of electrons

Bohr and the periodic table P is the elemental symbol for Phosphorus. 1.In which group is Phosphorus found? 2.In which period is Phosphorus found?

Bohr and the periodic table P is the elemental symbol for Phosphorus. Phosphorus has 5 valence electrons. How many electrons to be happy? If it received 3 more it would be fulfilled! And very HAPPY!

Bohr and the periodic table What is the charge of this Phosphorus ion? 3-

Day 3: Element Folder Due Friday at the beginning of class

Warm Up: 1.Look at your data from the physical properties lab 2.What did the compounds with HIGH melting points have in common 3.What did the compounds with LOW melting points have in common

Molecules Where to find molecules your element makes: ptable.com Click compounds tab Click your element Choose 1 from list

Bonding Vocabulary… to help you determine if your compound is ionic, covalent, or something else Electronegativity: Ability of atom to gain electrons Relative measurement – no units High (up to 4) – tends to gain electrons (right side of periodic table) Low (down to 0) – tends to lose electrons (left side of periodic table) Ionic Bond: Forms between atoms of metals & nonmetals Electronegativity difference >1.9, it’s ionic bond

A look at the Process Low electronegativity Na gives up e - High electronegativity Cl takes e - Becomes + Charged Becomes - Charged [ Cl ] - [Na] +

What Happens to Ions? Opposites Attract! [ Cl ] - [Na] + Note: Lewis Diagrams next to each other represents formula unit of NaCl

Covalent: non-metals electronegativity difference = 0 Elements in bond have same electronegativity Usually the same kind of atoms Ex: Cl 2, O 2, N 2 Look at Cl: Formula: Cl 2 Each Cl needs one electron; Neither will give one up; They SHARE This atom uses these electrons to follow the octet rule And so does this one.

Covalent: non-metals electronegativity difference = 0 Elements in bond have same electronegativity Usually the same kind of atoms Ex: Cl 2, O 2, N 2 Look at Cl: Formula: Cl 2 Each Cl needs one electron; Neither will give one up; They SHARE This atom uses these electrons to follow the octet rule And so does this one.

Polar Covalent Atoms in bond have slightly different electronegativity Electronegativity difference > 1.9: ionic bond Electronegativity difference < 1.9: polar covalent bond Electronegativity difference = 0: covalent bond Shared electron stays with more electronegative element more of the time

Polar Covalent Example Hydrogen Chloride: HCl H: electronegativity = 2.1 Cl: electronegativity = 3.2 Cl attracts shared electrons more than H Dipole forms because Cl becomes more negative and H is less negative Cl H 2.13.2

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