Chapter 1 Flashcards
Protons
- found in nucleus
- charge = 1.6*10^-19 OR +1
- Mass of 1 amu (atomic mass unit)
- Elements are defined by their # of protons
The atomic number (Z) is equal to
the number of protons found in an atom of that element
Neutrons
- Have no charge
- Found in nucleus with protons
Mass number
Sum of protons and neutrons in nucleus
Isotopes
- Share atomic # but different mass #s
- Only differ in number of neutrons, same amount of protons
Electrons
- Found in orbitals around nucleus
- Charge of -1
- Electrons closer to nucleus have lower energy
- Electrons farther from nucleus (higher shells) have more energy
Valence electrons
Electrons farthest from nucleus that have strongest interaction with surroundings and weakest interactions with nucleus
* Most likely to bond with other atoms due to weak pull from own nucleus
* Determine reactivity
Losing electrons yields
positive charge
Gaining electrons yields
negative charge
Positively chargted atom
Cation
Negatively charged atom
Anion
Atomic Mass
Nearly equal to mass number (sum of protons and neutrons)
Think mass … mass number
Atomic Weight
- Weighted average of all the different isotopes making up an element
- Number found on the periodic table
Think weight … weighted average
Mole
- Can be atoms, ions, molecules, etc.
- =6.02*10^23
Planck Relation
Planck’s constant
h=6.626*10^-34
Angular Momentum
h = Planck’s constant
n = principal quantum number
Energy of an electron
- Changes in discrete amounts with respect to the quantum number
- Energy of an electron increases (become less negative) the farther it is from the nucleus
R_H is the Rydberg unit of energy