MIDTERM STUDY (unit 3) Flashcards
Nucleus contains almost all of…
atom’s mass (p+ and n0)
Electron cloud contains almost all of…
atom’s volume (e-)
One amu = to what?
1/12 the mass of the carbon-12 atom
Balance between what holds atom together?
between electrostatic repulsion of like charges and electrostatic attraction of opp charges
Electron abt_________ the size of a proton
1/1800
Hyphen notation:
mass # written w/ hyphen after element name
Nuclear Symbol:
subscript = atomic #
superscript = mass #
Mass of particular isotope is = to?
protons + neutrons
of protons = ?
(Counting Subatomic Particles)
# of protons = ?
atomic #
of neutrons =?
(Counting Subatomic Particles)
# of neutrons = ?
Mass # - atomic #
of electrons = ?
(Counting Subatomic Particles) # 0f electrons = ?
atomic # ( in a neutral atom)
Isotopes:
atoms of the same element (same # p+) w/ diff # of n0 = diff mass
Some isotopes are…
stable and radioactive
Ions:
lost/gained e-
Cations:
(positive metals) formed when atoms lose e-
Anions:
(negative non-metals) Formed when atoms gain e-
Isotopes differ in # of n0 so differ in
MASS
Atoms differ by # of
protons
Ions differ by # of
electrons
isotopes differ by # of
neutrons
Average atomic mass:
weighted average of an element’s naturally occurring isotopes
(order) History of Development of ATomic Model:
- greek/ Dalton Billiard ball model
- Thompson’s Plum pudding Model
- Rutherford’s Nuclear model
- Bohrs Planetary model
- Quantum Mechanical model
Billiard ball model:
-Democtritus
-tiny solid, indestructible particles
Plum Pudding Model
-J.J thompson
- solid sphere w/ negativly charged e- embedded in ti
Rutherford model
- Earnest Rutherford
- atom is tiny, positively charged
- dense center
- mostly empty space
bohr’s Model (Planetary Model)
-Niels Bohr
Quantum mechanical model of the atom
-Many scientists
1ST advancement ( ball to plum) :
Thompson discovered (-) particles (electrons)
2ND advancement (plum to Ruther) :
Rutherford discovered atomic radius
3RD advancement (Ruther to Planetary) :
idea of fixed orbits (electrons traveling around)
LAWS AND THEORIES IN ORDER:
-Law of conservation of Matter
- Law of Definite Proportions
- Law of Multiple proportions
- Daltons Atomic theory
- QUantum Theory
The mole:
Unit of quantity -> 6.022 x 10 >23
atoms, formula units, molecules, grams, Liters ( LAFUMG)
Avogadro’s #:
6.022x10 >23
Liters to moles =
22.4L/mol
