Chemistry Test 3
What determines boiling point?
The stronger a molecule is, the higher the boiling point will be because when the molecules are bonded together, it is harder to break the bonding.
Why do metals conduct?
They have charged particles. All metals will be ionic bonded bc ionic bonding causes a charge when they give up/gain an e. The charged particles move around.
What are electron domains?
a concentration of electrons on one side of an atom
Why are bonds polar?
bc atoms of differing electronegativity are bonded together. the greater the difference in electronegativity, the greater the polarity is
Intermolecular force
force of attraction between molecules
Polyatomic Atom
has 1 ion but multiple atoms ex: (CO3) -2
How are intermolecular forces different than intramolecular?
they are the bonds between the covelant molecules . . .
Why do only polar substances dissolve?
they have a + and - end and the water (also + and -) will go through all the molecules and the water's - attraction will pull the molecules' + attraction and visa versa until it they all break apart and dissolve. Nonpolar molecules do not have + or - charges.
Why are halogens reactive?
they only need one electrons to complete their valence shell.
What does a metal atom need in order to form a cation? What does a metal atom need in order to form a cation?
A metal atom must give away electrons in order to form a cation (positively charged ion). A nonmetal must receive electrons to be negatively charged.
Atom & Molecules
A molecule is two or more atoms bonded together.
Why do metals form cations?
Metals form cations bc they only need to lose 1 or two electrons. When they lose electrons, they become positive and cations are positively charged ions. Nonmetals form anions bc they are closer to a full valence shell and they want to gain electrons. gain electrons-> become negative which makes them a negatively charged ion (a anion).
How do you name a molecule?
Prefixes: mono, di, tri, tetra, penta, hexa End in "ide" Always use prefixes except nvr begin with mono
How do you find out whether a molecule is polar? How do you tell what force it has?
. . . . . . .
How is an ion different from its parent atom?
An ion is different because it is + or - charged, which makes it different from the neutral state of the parent atom.
Why do hydrogen bonds have high BP?
As electronegativity difference increases, BP increases. HB have big electronegativty differences bc the bonds between H + N, O, & F are very polar.
How many valence electrons? What is its symbol? (As, Mg, Al)
As: 5 valence e. As-3 Mg: 2 valence e. Mg+2 Al: 3 valence e. Al+3
Name FeCl3 (How?)
Because iron is a transition metal, you must find the charge of clorine. Figure how many "Fe"s there must be to add up to Cl3. ->Iron (III) Cloride
Covalent, Ionic, Metalic, HB, DD, LD bonding
Covalent: strongest bc all the electrons are being shared with each other; intramolecular Ionic: strength comes from the + and - force of attraction; intra Metallic: electrons are shared & moving thruout the solid; conducts electricity bc it's moving; intra HB: When a molecule has H + N, O, or F DD: the + end of one molecule attracts the - end of another; the more polar the molecules are, the strngr the force is LD: always nonpolar; bigger the molecules are, the stronger; the temp dipoles due to random e movements attract each othr
How do you tell what kind of force a bond has?
Draw the lewis dot for the molecule. (Note: if it has a polyatomic ion, it will be ionic and cannot have a lewis dot.) Figure out the VSEPR shape it has. Find out whether it is polar, and then find the force it has.
How to find the formula of a molecule
Find the amount of valence electrons, and find the ions they make. Multiply them so they form a neutral bond. ex: Aluminun(3) and sulfur(6) -> Al+3 and S-2 -> Al2S3
If two molecules have the same force, how do you tell which one is stronger (& higher BP)?
Find the number of electrons in each, and the one with more is stronger because it is bigger!
Name these molecules: H20, CH4, NH3, AgCl, Cu2S
H20 = Dihydrogen monoxide CH4 = Carbon tetrahidride NH3 = Nitrogen trihidride AgCl = Silver (I) Nitrate Cu2S = Copper (I) Sulfide
Ion, Ionic Bond, & Ionic Compound
Ion: a charged atom Ionic Bond: when ones atom gives an electron to another and they become an Ionic Compound
What is a non-polar molecule?
It does not have polar bonds (<.5 EN) or the shape allows the polar bonds to cancel out. When a linear, tetrahedral, or trigonal planar have all the same atoms around the centr, it will cancel out and be nonpolar. (but no lone pairs!)
Explain how the octet rule describes how atoms form stable bonds.
It says that atoms tend to either have empty valence shells or full valence shells (8 electrons.) It describes how atoms form stable bonds because it insists that they will reach their full valence by making ionic or covalent bonds in order to become stable.
Why are LD forces more likely to be gasses and covalent bonds are solids?
LD force is weaker, so it cant hold the molecules together as well as a HB or covalent bond can.
What are the molecular shapes? (VSEPR)
Linear: 3 domains Trigonal Planar . . . Tetrahedron Pyramidal Bent . . .
