Adam Rohde

Particles

Protons: Positively charged particlesProtons: Positively charged particles Neutrons: Neutral particles Electrons: Negatively charged particles

Nucleus

Dense center of the atom Positively charged Consists of protons and neutrons Determines what the element is Contains most of the mass

Electron Cloud

Orbits the nucleus Consists of electrons Takes up most of the space Does not contribute to atomic mass

Atomic Mass

Number of protons and neutrons Atomic mass units (amu) 4 protons + 3 neutrons = 7 amu Electrons are not counted

Nuclear Force

Protons repel each other Held together by strong nuclear force Have to be extremely close Exchange mesons

Atomic Charges

Relative to protons and electrons # of protons > # of electrons: + charge # of electrons > # of protons: - charge # of protons = # of electrons: neutral Neutrons are not counted

Elements

Depend on # of protons # of protons decides placement on the

periodic table Can have different charges Can have different # of neutrons

Ions

Same elements Different charges Hydrogen with 2 electrons: - 1 Hydrogen with 1 electron: neutral Hydrogen with 0 electrons: + 1

Isotopes

Same element Different masses Hydrogen with 1 neutron: 2 amu Hydrogen with 0 neutrons: 1 amu

Periodic Atomic Mass

Mass displayed on the periodic table Average mass of the isotopes Used when determining quantities of

molecules

Quantities

Mass (grams) Moles Molarity

Avogadro’s Number

Used often if chemistry Number of molecules in 1 mole 6.022 x 10e23

Moles

Can be determined from mass Grams / atomic mass Ex: 28g of N / 14 amu = 2 moles

Molarity

Concentration in a solution # of moles / liters of solution Ex: 2 moles of HCl / .5L = 4M

Review

Structure of atoms Charges of atoms Mass of atoms Quantities

References ion. (2009). In Merriam-Webster Online Dictionary.

Retrieved October 1, 2009, from http://www.merriam-webster.com/dictionary/ion

isotope. (2009). In Merriam-Webster Online Dictionary.Retrieved October 1, 2009, from http://www.merriam-

webster.com/dictionary/isotope The Strong Nuclear Force. (n.d.). Retrieved October 1, 2009, from

http://aether.lbl.gov/elements/ stellar/strong/strong.html

Weisstein, E. W. (n.d.). l. Retrieved October 1, 2009, from http://scienceworld.wolfram.com/physics/

AvogadrosNumber.html