Ionic bond: forms between ions. Electrostatic attraction holds ions together. ( Nonmetal + metal)
Electronegativity: calculation how strongly an element pulls an electron towards its nucleus
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
Non - Polar Covalent = 0 Polar Covalent = 0.1 - 2.1 2.1 and higher = Ionic
Delta Polarity: forms when 2 nonmetals of of different EN bond together. -Unequal sharing of electrons - results in poles on - and + charges
Intermoleular forces: are weak forces that are found between molecules.
Intramolecular forces: are strong forces that holds atoms together in a molecule.
Chemical Bonding 2:
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!
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.
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
Unit 6: Chemical Reactions:
Chemical equation describes chemical reaction using formulas and symbols
Reactants turn into products A + B = C + D
Physical states of reactants and products: -Gas (g) -Liquid (l) -Solid (s) - (Aqueous)
Exothermic: energy is released into surroundings Exothermic: energy is absorbed through the surrounding.
Balancing Reactions: a balanced reaction has same number of atoms of each element on both sides.
How to balance chemical equations: - multiplying and placing coefficient in front of each substance - coefficient can multiply all subscripts
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.
