Covalent compounds The “why can’t everybody just be friends” bonding…

So…. How did you get full outside energy levels of valence electrons this time??? Oh… Covalent Compounds: 2 or more non-metals held together by a covalent bond. Covalent bond: the sharing of electrons between atoms. Like two people listening to the same song with ear buds/headphones yarp

Same goal of universe… Lazy… low in energy, stability How did ions fill up their outer energy level?? What held together ionic compounds?? Covalent compounds still want full outer energy levels of e -. But… they do it why sharing Show it on the periodic table!!!!!!! Yarp

How come??? Why share??? Take a step back… use old knowledge – Metals… gain or lose e - ??? – Nonmetals … gain or lose e - ??? Ionic compounds have metal and nonmetal – one loses e -, the other one gains e - … Covalent compounds only made of nonmetals – Who will lose e - ??? Correct… makes sense? yarpness

Why don’t you draw a picture… it’ll last longer… Show the story of 2 non-metals eventually sharing an electron

How do we show the sharing??? we call it Electron dot structures. the cheerio lab… and here are the rules!!! 1. Determine the total # of valence electrons in a compound Add up all valence electrons of each atom in the compound yarp

2. Arrange the e - to show complete outer energy levels for ALL atoms in the compound!!!! Each atom should have 4 pairs (8 e - ) around them. Except hydrogen = 1 pair (2 e - ) Are side-by-side or up and down. Not diagonal!!! yarp

3. Replace each shared pair of electrons with a connecting line This line represents a pair of electrons and a covalent bond!!!! yarp

Examples… show bond type!!! CBr 4 = carbon tetrabromide

CO 2 = carbon dioxide CO = carbon monoxide

Naming of covalent compounds Need prefix memorized!!! 1 = mono6 = hexa 2 = di7 = hepta 3 = tri8 = octa 4 = tetra9 = nona 5 = penta10 = deca

Learn the rules!!! Rule the rules CBr 4 = carbon tetrabromide CO 2 = carbon dioxide CO = carbon monoxide P 2 O 3 = diphosphorus trioxide

Compare covalent and ionics pt. 1 characteristicCovalentionic Atom types (metal, nonmetals, etc) How bonded Unique naming tricks

More practice if ya need it!!! e- dot Sulfur dichloride Freon = CCl 2 F 2

And even more practice… awesome Work hard… Yarp more

Covalent part 2 Ya better have done the property lab

Did you??? Summarize the covalent lab in class??? Compare covalent compound properties to ionic compound properties??? Yes??? It should have taken some time… Yes??? Sweet move on!!!! Yarp!

Diatomic molecules Two of the same atom covalently bonded together… Memorize the 7 All are followed by the word molecule HYDROGEN MOLECULE H 2 = hydrogenCl 2 = chlorine N 2 = nitrogenBr 2 = bromine O 2 = oxygenI 2 = iodine F 2 = fluorine

Sharing doesn’t mean equal Electronegativity: an atoms pull of electrons in a covalent bond. Some pull stronger than others when sharing electrons yarps

Subtract the difference in Electronegativity Bond typeHow electrons are shared Electronegativity difference Non –polarEqual sharing# ≤ 0.4 PolarUnequal sharing# > 0.4 IonicNot sharing, taking # > 2.1

Electronegativity #’s!!!

Enough…!!!! For now!!!! Use this to work on the model lab… Lots of electron dot practice here… Get to work… And you will like it!!!

3-D shapes Tinker toy coolness!!!

5 shapes to talk about Draw em on da chalkboard!!! Show models Show angles and shared/no shared Linear = line Tetrahedral = tripod with neck Pyramidal = tripod no neck Bent = bent Trigonal planar = flat… like pancake yarp

Add some polarity How the electrons are shared in a covalent bond make a big difference. Non-polar = equal sharing and balance of electron and charge – Like oil Polar = unequal sharing and a shift in negative charge – Like water yarp

Like dissolves like Polar/ionic things dissolve in polar things – Things dissolving in wa wa Non-polar things do not dissolve in polar things – Oil and wa wa don’t mix How do you know if it is polar or non polar? Yarp that

Compare Electronegativity To find polarity 1. identify the 2 elements sharing in a bond 2. subtract bigger Electronegativity from smaller Electronegativity. 3. compare difference Bond typeHow electrons are shared Electronegativity difference Non –polarEqual sharing# ≤ 0.4 PolarUnequal sharing# > 0.4 IonicNot sharing, taking# > 2.1

Do some examples Carbon tetrahydride Chloromethane (you won’t have this name) Carbon dioxide water

Now you know the bonds You can also look at the entire molecule as well Polar molecule = an unbalance when comparing the bonds of the molecule Non-polar molecule = a balance when comparing the bonds… The rules get detailed… we no bother Show in the drawn molecules yarp

We be done… Is good Is done… Is review yarp