Atomic structure Flashcards
What did Boyle propose
Elements can’t be broken down into anything simpler
What is boyles law
Volume is inversely proportional to pressure at constant temperature
What was lavoisiers law of conservation of mass
Matter is neither created nor destroyed in a chemical reaction, simply rearranged
What did Davy do
Discovered new elements Na, K, Ca etc using electrolysis
What was daltons atomic theory
Elements are made of tiny particles, all particles of element are identical, compounds are chemical combinations of these particles
What was dobereiners law of triads
Groups of 3 elements with similar properties, one intermediate in properties
What was newlands law of octaves
Properties repeat every eight element (when arranged in order of mass)
No noble gases as they were not discovered at the time
What did mendeleevs periodic table look like
Arranged elements by property space rather than just weight, left gaps, predicted properties of elements to go in gaps e.g. scandium
What did Moseley do
Gave us atomic number (no. Of protons in an atom)
Modern table vs mendeleevs
Modern Mendeleevs
-No gaps -gaps left for undiscovered elem’s
-Noble gases present -noble gases absent
-Transition elements in -transition elements not in sep block
Separate block -elements in order of atomic mass
-Elements in order of atomic
Number
What did Democritus (Greek) say
Atoms are indivisible
4 elements - earth, wind, fire, water
Describe crookes Maltese cross experiment
Hot negative electrode (cathode) produced rays that caused a phosphorescent screen to glow in a vacuum tube.
Crookes called these cathode rays.
Rays could be blocked by a metal cross shape and a shadow of the cross is cast on the end of the tube
What was Thompson’s contribution
Deflected cathode rays with charged plates so they must be negative!
Called them electrons(coined by stoney)
Magnet also deflect rays
Proposed plum pudding model of atom - negative electrons in a positive dough
What did Millikan do
Discovered the mass of the electron using Oil drop experiment, calculated the mass of the electron using the charge/mass ratio
What did Rutherford do
Discovered the nucleus using gold foil experiment
[fired alpha particles from radioactive source in block of lead at very thin gold leaf, alpha particles seen as flashes of light on fluorescent screen]
-almost all passed though - so atom mostly empty space and nucleus is very small
-some deflected - so nucleus positive(like charges repel)
-some bounced straight back - so nucleus is very dense (lot of mass)
What did bohr say
Electrons orbit nucleus in shells
Gave us Bohr model
[n=shell number]
What did Rutherford discover
Protons when bombarding nuclei with alpha particles, suspected other particles were needed to hold protons together
What Chadwick discover
Neutrons by bombarding Be with alpha particles
Describe atoms
No charge, tiny, 6x10^23 particles
Describe molecules
Groups of atoms chemically joined
Describe ions
Atoms that have a charge
What is the mass, charge and location of the proton
Mass 1
Charge +1
Location nucleus
What is the mass, charge and location of the neutron
Mass 1
Charge neutral
Location nucleus
What is the mass, charge and location of the electron
Mass 0
Charge -1
Location orbiting nucleus
