SUMMARY SHEETS

Mere som dette

ΕΚΦΟΒΙΣΜΟΣ

af ΚΩΝΣΤΑΝΤΙΝΑ ΛΑΖΑΡΗ

Paranormal phenomina

af Alise Ford

Elements

af Woon Kiat

Objects and processes inside cells

af Samantha Escamilla

References: -https://www.youtube.com/watch?v=NFqnqGwLuGc -https://www.youtube.com/watch?v=6upVmuZFN5I https://upload.wikimedia.org/wikipedia/commons/3/39/Carbon-fluorine-bond-polarity-2D.png

Counting atoms: - Symbol of elements represents 1 atom of that element. e.g: Ca = 1 carbon - Subscript is written on lower right hand and represents # of atoms in that element e.g:N sbs 2 = 2 nitrogen - Subscript outside brackets multiplies everything inside. e.g: Ba sbs 3 (po sbs 4)sbs 2 = 3 barium, 2 phosphorus, 8 atoms of oxygen - coefficient infront represents # of atoms for that symbol.

How to balance chemical equations: - multiplying and placing coefficient in front of each substance - coefficient can multiply all subscripts

Balancing Reactions: a balanced reaction has same number of atoms of each element on both sides.

Exothermic: energy is released into surroundings Exothermic: energy is absorbed through the surrounding.

Physical states of reactants and products: -Gas (g) -Liquid (l) -Solid (s) - (Aqueous)

Reactants turn into products A + B = C + D

Chemical equation describes chemical reaction using formulas and symbols

Unit 6: Chemical Reactions:

Diatomic molecules: form when 2 non metals of different EN bond together. -equal sharing of electrons - no pole of charge + and - - found in pairs 2 bonded together = *H2 O2 F2 Br2 I2 N2 Cl2

VSEPR stands for : Valence, Shell, Electron, Pair Repulsion. = explains shapes of molecules. Bonding and non- bonding electron pairs will be farthest apart from each other so they don't repel.

Lewis structures: how to draw lewis structures: - Count valence electrons for each element and add them. - Put the element that has least # of electrons in the center and draw bonds to connect it to other elements - keep adding electrons until all of the elements are happy, fill the octet!

Chemical Bonding 2:

Intramolecular forces: are strong forces that holds atoms together in a molecule.

Intermoleular forces: are weak forces that are found between molecules.

Delta Polarity: forms when 2 nonmetals of of different EN bond together. -Unequal sharing of electrons - results in poles on - and + charges

Non - Polar Covalent = 0 Polar Covalent = 0.1 - 2.1 2.1 and higher = Ionic

Calculating EN values: Use the EN value chart to find the difference between the EN of 2 elements. To find the difference subtract the least EN from the most EN H=2.1 , F=4.0 = 4.0 - 2.1 =1.9 = Polar covalent

Electronegativity: calculation how strongly an element pulls an electron towards its nucleus

Ionic bond: forms between ions. Electrostatic attraction holds ions together. ( Nonmetal + metal)

Covalent bonds: Electrons shared between 2 atoms ( Nonmetal + Nonmetal)

Unit 4 : Chemical Bonding