Structure and Properties Flashcard

J.J Thompson- 1897

-Matter is composed of atoms that contain electrons

-Ex: blueberry cake

cake is positive(protons)

blueberries are negative(electrons)

John Dalton-1805
Matter is composed of indestructable, indivisable atoms which are identical for one element, but different for another
Ernest Rutherford-1911

-An atom is composed of a very small nucleus, which contains positive charges and most of the mass of the atom. The rest of the atom is made up of mostly empty space with very small negative electrons occupying the surrounding area.

-Proved this with gold foil and gamma rays

-some rays went through, some deflected back at different angles. Therefore some sort of positive center or nuclues, and the rest of the atom is mostly empty space

Rutherford and Associates
-Proton has an equal and opposite charge to and electron and is 1836 times its mass.
James Chadwick-1932
-Nucleus also contained neutrallly charged particles called neutrons. This explained isotopes
Isotope

-Atoms with the same number or protons, but differnt number of neutrons

-Ex: C-12, C-14

Standard Atomic Notation

A: Mass Number

Z: Atomic Number

-Ex: C-12   126C

Radioisotope
-An isotope that emits radioactive particles as it decays
Planck’s Quantum Hypothesis

-Energy could be gained or transfered in whole-number quanties

-Light it emitted in bursts, packets or quantites of energy. IT IS NOT CONTINOUS

-Photon: unit of light energy

Quantum Numbers
-It is impossible to simultaneuosly know the exact position and spped of an electron.
Orbital
-The region around the nucleus where there is a high probibility of finding an electron
Ground State
-An electrons lowest, most stable energy level
Orbit vs. Orbital

1. Well defined circular path;; 1. Region of space

2. 2-D motion;;;;;;;;;;;;;;;;;;;;;;; 2. 3-D motion

3. Max electron is 2n2;;;;;;;;;; 3. Max electron is 2

4. Circular shape;;;;;;;;;;;;;;;;;; 4. different shapes

What the quantum number do

-They describe the quantu mechanical properties of orbitals

Principle (n)

Seconday (l)

Magnetic (ml)

Spin (ms)

Principle Quantum Number (n)
-The energy level the electron is located (shell)
Secondary Quantum Number (l)

-Describes the shape of the orbital

0=s orbital (shpere)

1=p orbital (peanut)

2= d orbital (2 peanuts)

3=f

4=g

1=n-1

-Ex: 3n, 1=2,1,0(d,p,s)

;

Magnetic Quantum Number (ml)

;

-Describes the orientation of the orbital in space relative to the other orbitals

-ml= -l to +l

-Ex: l=2 ml=-2,-1,0,1,2 (5 different orientations)

Magnetic Spin (ms)

-+1/2 counterclockwise

– -1/2 colckwise

Two electrons in the same shell must be spinning oppositly of each other

Pauli Exclusion Principle
Every electron in an atom will have its own set of 4 quantum numbers
Hund’s Rule
In a set of orbitals with the same energy level, the lowest energy configuration for an atom is the one with the max number of unpaired electrons. This means that before any 2 electrons can occupy an orbital in a subshell, other orbitals in the sam esubshell must have one electron occupying it already.
Aufbau Principle
An atom is “bulit up” by the additon of electrons which fill orbiats starting at the lowest availibe energy orbital beofre filing higher energy levels
Energy Level Diagrams-Anions
-Just add extra electrons
Energy Level Diagrams-Cations
-Do full E.L.D, then substract amount of charge from the highest possible energy level

Electron Configuration

Na

Sn+1

Na:1s2, 2s2, 2p6, 3s1

Sn+1: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10

Short Hand E.C

Al

Al: [Ne] 3s2, 3p1,

Anomilies

Cr, Cu

Cr:[Ar]4s1, 3d5

cu:[Ar]4s1, 3d10

-it is more stable to have half filled orbitals then orbitals with empty spaces

Magnetism

Ferromagnetism: Ni, Co, Fe

Paramagnetism: weak magnetic field

Polar Molecules

-Electronegatitives between 0.4 and 1.7

-If a symmetrical coumpond has polar bonds, the total compund is non polar, because each bond is beinnging pulled in equal and opposite directions

Non Polar Molecules

-Electronegativites between 0 and 0.4

 

Ionic Molecules

-Electronegativites 1.7+

-Usually between metals and non-metals

Ionic Solids

-Metal(anions) and non-metals(cations)

-ex: NaCl

-hard, britte, high melting/boiling points

-crystal

 

Metallic Solids

-Metals

-ex: Zinc/Iron

-shiny, silvery, flexible and conduct electricity/heat

-nuclei are fixed and valance electrons are mobile (electron sea)

-Electrons act as glue to hold nuclei together

-strong bonding (+nuclei and -valance electrons)

Molecular Solids

-Non-metals

-ex: iodine, carbon dioxide

-low melting/boiling point, non conductors

 

Covalent Netwrok Crystals

-ex: diamond and graphite

-very hard and strong, high boiling/melting points

-some can conduct electricity (graphite)

 

VSEPR Theory

A= central atom

X= bonding electrons

E= unbonded electron pairs

-Valance Shell Electron Pair Repulsion Theory

-helps you to predict the shape of molecules due to their bonding and non-bonding pairs of electrons

 

Linear

-AX2

-180°

Trigonal Planar

-AX3

-120°

Tetrahedral

-AX4

-109.5°

 

Trigonal Pyramidal

-AX3E2

-Less than 109.5°

 

V-Shaped/Bent

-AX2E2

-109.5°

Trigonal Bypyrmadial

-AX5

90° and 120°

Seesaw

-AX4E

 

Octahedral

-AX6

90°

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