Energy, Atoms and Molecules

EnergyEnergy

The capacity to do work or produce heat

Measured in calories or JoulesLaw of Conservation of Energy: E is neither created nor destroyed

Temperature is a way to measure heat energy.

Celsius vs KelvinsCelsius vs Kelvins

MatterMatter

Anything with mass and volume

Physical changes = crushing, tearing, state changes

Chemical Changes = alter the chemical identity of the substance

Law of Conservation of Law of Conservation of MatterMatter

Matter is neither created nor destroyed

ElementsElements

A substance that cannot be separated into simpler substances by chemical change.

Elements are composed of atoms.

Where did elements come from?Where did elements come from?

Making the Periodic Table of Elements via Stellar Evolution

Helium Fusion in Stars Creating Carbon and Beyond Up to Iron The Relative Abundances of the

elements reflect these fusion reactions. Elements divisible by 4 are the most abundant.

What Symbols?What Symbols?

Learn the first 54 element symbols !

Hydrogen (#1) = HHelium = HeLithium = LiBeryllium = BeTo (#54) Xenon = Xe

Nemonics and tools:

Au, give me your gold!Cu in the copper mine!

Did you hear about the date between oxygen and potassium? (it was OK)!

Did you hear about the date between oxygen and magnesium?(it was OMG)!

CompoundsCompounds

Two or more atoms bonded together.

MixturesMixtures

Heterogeneous- visibly different parts of a mixture

Homogeneous- looks the same throughout

Atomic SizeAtomic Size

Atoms are unbelievably tiny. How tiny? Incredibly smaller than plant and animal cells. Billions of atoms make up the writing tip of your pen or pencil.

Atom CharacteristicsAtom CharacteristicsAll matter is made of atoms.Space (without any particles) has no atoms.

Atoms are made of smaller particles protons +

neutrons ( ) and electrons (-) Protons, neutrons, and electrons, of course, are made of even smaller particles…

Sub-subatomic Sub-subatomic particlesparticles

Protons, electrons and neutrons are made of even smaller particles including,

Quarks, bosons, fermions, mesons, etc.

Particle physics studies these entities (you don’t need to know these in Chem 1 &2).

ProtonsProtons

Positvely chargedEquals the atomic number of an atom.

Always stays the same for an element.

Located in the nucleus of the atom.

NeutronsNeutrons

Neutral chargeNumber of neutrons = Atomic mass minus the atomic number.

Different isotopes have different numbers of neutrons.

Always reside in the nucleus. (a neutron walked into a bar)

ElectronsElectrons

Negative electrical charge Electrons equal protons in atoms.

Missing electrons make positive ions.

Extra electrons make negative ions.

Located in shells outside nucleus.

The End of Part 1The End of Part 1

Hot or Not?

Definitely Definitely HOTHOT!!

ISOTOPESISOTOPESMany elements have different types of Many elements have different types of atoms, each with different numbers of atoms, each with different numbers of neutrons. Each type is called an neutrons. Each type is called an isotope. Hydrogen has 3 isotopes: H-1, isotope. Hydrogen has 3 isotopes: H-1, H-2 and H-3.H-2 and H-3.

IsotopesIsotopes

Isotopes with higher numbers of neutrons than normal tend to be radioactive. For example, H-3 or tritium isotopes tend to spontaneously give off electrons called beta particles. This is called radioactive decay. How do they do this?

RadioactivityRadioactivityMost elements have isotopes that give off neutrons or protons or electrons spontaneously into space at high speeds.

Alpha Particle = 2 protons and 2 neutrons

Beta Particle = electronGamma Ray = electromagnetic wave.All three types of radiation are ionizing (dislodge electrons and cause chemical reactions to happen)

Radiation TypesRadiation Types

Penetrating Penetrating PowerPower

paper stops alphapaper stops alpha

aluminum foil stops betaaluminum foil stops beta

thick lead or concrete stops gammathick lead or concrete stops gamma

Natural Radioactive Natural Radioactive DecayDecay

Nuclear Chemistry Review LinksNuclear Chemistry Review Links

http://www.visionlearning.com/library/module_viewer.php?mid=59

http://www.furryelephant.com/player.php?subject=physics&jumpTo=re/2Ms4

Finding Average Atomic MassFinding Average Atomic Mass

The average atomic mass (protons and neutrons) is the weighted average of the different isotopes.

weighted mass =

% abundance X mass

% abundance X mass = weighted massCl-35 75.53 x 34.97 = 26.41Cl-37 24.47 x 36.97 = 9.04 Average atomic mass = 35.45

IonsIonsSodium has 11 protons and 11 electrons. When it loses an electron, it becomes a cation with a +1 charge, Na+1

Chlorine has 17 protons and 17 electrons. When it steals sodium’s electron, it will have 18 electrons, and becomes an anion with a –1 charge. Cl-1

+cations and - anions

Ion ExamplesIon ExamplesPositive and negative ions are attracted to each other and form ionic bods to make a compound.

Na+1 Cl-1

Sodium and chlorine bond to each other to become a formula unit of sodium chloride.

Atoms and Compounds:Atoms and Compounds:

Hot or Not?

Definitely Definitely HOTHOT!!

The EndThe End