Chem final

formal charge

# of valence electrons - ( # dots + # lines), helps you find most favorable structure(best structure has fc=0 with neg fc on most e neg atom

Steps to drawing a Lewis diagram

1. Sum the valence electrons 2. Draw symbols with least eneg in middle (except H) and connect everything with single bonds 3. Make everything octet by adding dots 4. Count and compare to electrons in step 1 5. If you have too many e- make multiple bonds, if you have too few add extra to the central atom even if it exceeds octet, add ion bracket if you need to

How many Carbon atoms are contained in 2.8 g of C2H4

1.2 x 10^23(molar mass, avagadros, mol to mol)

What is the electron configuration of K +

1s2 2s2 2p6 3s2 3p6

What is a ground state e- configuration for an atom of Se

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4

1atm

760 torr and 760 mmhg

temporary dipole

A molecule where a temporary imbalance in the electron cloud causes a momentary imbalance of charge.

What is a pure substance

A single element(cannot seperate) or compound( seperble into simpler substances), not mixed with any other substance

Electronegativity

Ability of atom in a bond to attract e—, small atoms w large nuclei have, upper right, IE jumps from valence to core e-

expanded octet

An exception to the octet rule that permits atoms in the third row or lower on the periodic table to have more than eight electrons in a Lewis structure., easier when lone atom is big and multi plicated atom is small(in e neg)

Stronger bonds..

Are atoms closer in e- levels

What does a metallic bond look like

Array of positive metal ions surrounded by a sea of e-(delocalized)

What is the difference between an atom and an ion

Atoms have equal numbers of protons and electrons, resulting in no charge. Ions have gained or lost electrons, resulting in an overall charge.

Which elements have 6 e- to reach octet?

Be and B

Characteristics of covalent network solids

Between nonmetals, covalently bonded into 3d network, high mp, rigid and hard bc covalent bond angles are fixed, sheet itself held by cov bonds, sheet on top of sheet by ldfs, 1) crystalline= repeating pattern shape 2) amorphous= not repeating pattern shape

How do you find polar news in a bond btw two atoms

Biggest electronegativity- smallest eneg (.5 or less=non polar covalent, .5-2.0= polar covalent, 2.0+=ionic) larger dif= more polar

resonance structure

Bond can be anywhere but is needed

Physical traits of ionic bonds

Brittle(crystal lattice), crystalline, high mp( formula units in crystal lattice strongly attracted takes more e to overcome attractions), conduct e- in h2o(bc dissolve and dissociate into free flowing ions and free flowing ions conduct), cant conduct as a solid bc no free flowing ions, typically colorless or white crystals

The compound CCl4 is nonflammable and was once commonly used in fire extinguishers. On the basis of periodic properties, which of the following compounds can most likely be used as a fire resistant chemical? A. Bcl3 B. Ch4 C. Cbr4 D. Pbcl2

C

Which has the smallest radius and why Cl-, ar, k+, ca2+

CL minus, because its nuclear charge exerts the least attractive force on the electrons in the 3P sub level

Most ionic? CCL4, cucl2, cacl2, ncl3

CaCl2

Characteristics of mcc solids

Covalently bonded mcc attracted to each other through weak imfs, low mp, dont conduct bc Val e nit free held within cov bonds

What are the two types of network covalent solids

Crystalline- pattern, amorphous- no particular shape

A. RBCL has a high boiling point. Which of the following compounds is also likely to have a high boiling point, and why? b. NO, because its elements are in the same period of the periodic table C. CLF, because its elements are in the same group of the periodic table D. CL20, because its elements have similar electronegativities and it is a covalent cmpd

D

Which of the following correctly compares periodic properties of two elements and provides an accurate explanation for that difference A. The first ionization energy of Al is greater than that of B because AL has a larger nuclear charge than B does B. The first ionization energy of F is greater than that of O because O has a higher electronegativity than F has C. The atomic radius of CA is larger than that of MG because the valence electrons in MG experience more shielding than the valence electrons in CA do D. The atomic radius of CL is smaller than that of S because CL has a larger nuclear charge than S does

D

Which of the following correctly identifies which has the highest first ionization energy, CL or Ar, and supplies the best justification A. CL because of its higher electronegativity B. CL because of it's higher electron affinity C. AR because if it's completely filled valence shell D. AR because of its higher effective nuclear charge

D

hydrogen bonding

Dipole dipole(strong) H atoms covalently bonded to to N,O, or F, can't have can experience or do

What is an alloy

Doesnt have constant composition, combining of 2 or more elements, 2 types

What must you do before determining electron domain and mcc geometry

Draw the Lewis diagram

Ionization energy

E required to remove VALENCE e-, IE directly proportional to fatt and magnitude inversely proportional to distance

Photoelectron spectroscopy

Each peak represents a sub shell, height =number of e- in that sub shell

What is a mixture

Either homogeneous( looks the same throughout) or heterogeneous (does not)

Bond energy

Energy required to separate atoms

Lattice energy

Energy required to seperate ions in ionic bond(directly proportional to fatt)

binding energy

Fatt or e that holds e- close to nucleus

Unshared pairs

Give polarity

magnitude

Greatness of size, strength, or importance(protons)

Metallic solid characteristics

Has sea of e- so great conductors, malleable, ductile(have charges on particles-dif btw them and interstitial alloy)

The Melting point of MGO is higher than that of NAF. Explanations for this observation include which of the following? I. MG 2+ is more positively charged than na+ II. 02- is more negatively charged than F- III. The O2- ion is smaller than the F - ion

I and II

What are the 2 types of alloys

Interstitial(form btw atoms w dif radii- smaller atoms fill interstitial space) and substitutional alloy(atoms of comparable radius but still not constant composition bc that's the dif btw an alloy and a compound)

When do you have ionic vs covalent character

Ionic when big difference in enegs, covalent when difference is small

Three types of bonds

Ionic( e- transferred from cation to anion to reach octet, metal & nonmetal, they stick), covalent(2 neutral atoms with positive nucleus and "negative middle" btw them, 2types= polar-shared e- and non polar= non shred e-, not permanent, return to parent atoms when bonds break, sharing e- in bond), metallic(e- move freely between nuclei-called delocalized e- or sea of e-, sea of e- allows metallic bonds to be malleable, ductile, and conductive)

What do mass spectrum graphs measure

Isotope abundance

What is the VSEPR theory?

It predicts the shapes of molecules based on the idea that electrons repel each other.

What is gravimetric analysis?

Lab where you pour thing and the precipitate dries

What is a network covalent solid

Large conglomeration of covalent mcc( crystals look ionic but connected w solid lines) 2 types

What is the electron geometry for two domains

Linear, 180 degrees(no mcc options)

Physical traits of covalent bonds

Low mp(bc no crystalline structure), dull, dont conduct e- bc no dissociated e-, poor heat conductors

Characteristics of ionic solids

Low vapor pressures, high melting points, high boiling points, brittle because sheets Slide Over each other and charges repel, conduct when melted

What is a mass spectrometer

Mass spectrometry involves firing molecules of varying weights through a circular tube and a magnetic field. The higher the molecule's weight, the less it is deflected by the magnetic field. The lower the molecule's weight, the more it is deflected by the magnetic field. We can use the differences in their deflection to separate molecules and identify them individually.

When drawing compound

Must look at atomic radius size and draw true to size(largest in bottom left)

Which of the following compounds contains both ionic and covalent bonds SO3, C2H5OH, MgF2, H2S, NH4Cl

NH4Cl

Gas

No fatt or imfs

Inter nuclear distance

Nucleus-nucleus, proportional to atomic radius and energy levels

Factors affecting pressure

Number of collisions, mass of particles, speed at which particles collide

bond order

Number of lines(bonds) divided by binding regions(everywhere there is a bond) ex: triple bond and single bond is 4/2

What math problems do you have to do for 1.1-1.4

Number of moles of precipitate produced in an expirement, mass percent of x in tablet, identifying xcl, limiting reactant problems, calculate theoretical and percent yields, filtration with filter paper problem

Density

P molar mass/ RT

How do you calc effective nuclear charge

P+ - core e-

Comparing 2 components

P1v1/T1n1= P2V2/T1n2

Ideal Gas Equation

PV=nRT (0.0821 latm/molk)

How do you do a mol fraction

Part interested in/ all of mol mixture

In a bond where do the partial charges go

Partial neg charge goes on atom w highest electronegativity

Kinetic mcc energy predicts

Pressure increases as temp of gas increases bc both gas mcc collide more frequently with the wall and the gas mcc collide more energetically with the wall

Excess reactant

Reactant that is left over

To determine the percentage of water in a hydrated salt a student heated 1.2346 g sample of the salt for 30 minutes when cool to room temperature the sample weighed 1.1857 g after the sample is heated for an additional 10 minutes and again cooled to room temperature sample weighed 1.1632 g which of the following should the student do next

Reheat the sample until its mass is constant

What's a chemical bond

Requires a transfer or sharing of electrons and attractions can exist without being bonded(mixtures not chemically bonded.

interstitial alloy characteristics

Rigid bc of interstitial atoms (not charged particles), retains sea of e- so conducts

How do you find number of valence electrons

S and p in the highest energy level( other electrons are core)

analogous compounds

Same groups will bond similarly

Physical trait of metallic bonds

Shiny, malleable(bends), ductile(stretches), conducts e- in both liquid and solid form, good heat conductors, high melting point, all caused by sea of electrons

What is electron domain with four domains

Tetrahedral(109.5), 3 bonding &1 nonbonding is trigonal pyramidal, 2 nonbonding&2 bonding is bent

The further an e- is from a nucleus

The easier it is to remove and the less Ionization Energy it takes

What's electron domain geometry

The five basic shapes with all domains bonding

London dispersion forces

The intermolecular attractions resulting from the constant motion of electrons and the creation of instantaneous dipoles. - increase with contact area(size of e- cloud based on molar mass) and polarizability(more e- in cloud)

In his atomic theory, Dalton proposed that all atoms of a given element are identical. Which of the following observations provides the best evidence that the proposal is incorrect

The mass spectrum of cu has a peak at 63 amu and another at 65 amu

In general when choosing between Lewis structures..

The preferred structure is always the Lewis structure where octet is satisfied without using multiple bonds, even if fc isn't ideal

Where do the electrons in a bond shift

Towards the atoms with the negative partial charge( highest eneg), dipole points toward most eneg atom

Electron domain with five domains

Trigonal bypyramidal(120 in triangle and 90 btw up and down and triangles), 4 bonding 1 nonbonding= seesaw, 3 bonding 2 nonbonding= t shaped, 2 bonding 3 nonbonding= linear

What is electron shape with three electron domains

Trigonal planar(120 degrees), bent(mcc with one nonbonding side)

IE highest where

Upper right(dist trumps magnitude)

What makes gases less ideal

Volume down, temp down, pressure up bc they create imfs bc they're moving slow

When do ionic compounds conduct electricity

When they have charged particles and the particles are free to move

ion-dipole forces

attractive forces between an ion and a polar molecule

Atomic and ionic radii

decrease as you move left to right & increase as you move down

gas to solid

deposition

dipole-dipole forces

forces of attraction between polar molecules - the greatest bc act in addition to ldfs

What is an electron domain

in the VSEPR model, a region about a central atom in which an electron pair (bonding or nonbonding) is concentrated

What is a binding pair vs a non bonding pair

line, dots that don't bond

6 electron domains

octahedral( 90), 5 bonding 1 non= square pyramidal, 4 bonding 2 non= square planar

What are the two types of matter

pure substances and mixtures

What's molecular geometry

resulting shape after accounting for unshared pairs, repulsion's taken into account

Graham's law of effusion

skinny manny gets through, fatty chuck gets stuck, r1/r2=square root m2/m1

What is kinetic energy proportional to?

temperature

What is a limiting reactant

the reactant that runs out first and limits the amount of product that can be made

What is electron affinity

the tendency of an atom to attract electrons, the more neg kJ/mol the more likely it is to absorb, absorbing lowers pe