Chemistry Unit 1 Flashcards
Mass number
Total of # protons and neutrons
Atomic mass
Mass of atomic particle
Ex(6.54518)
Isotopes
of nucleons in the nucleus, is the atoms mass number, and each isotope of a given element has a dif mass #
Three subatomic particles
Proton( positive nucleus and responsible”)
Neutrons( neutral nucleus and responsible)
Electrons( negative electron cloud and volume)
The number of neutrons in an atom can be determined by using the following equation.
Mass - # of protons= neutrons
Democritus
Magic contribution/ discovery:
Why wasn’t he completely correct?
Discovering the atom
There are subatomic particles
John dalton
Five principles of his atomic theory
- All things are composed of indivisible participles called atoms
- All atoms of a certain elect are identical atoms
- Atoms of different elements are different
- Compounds are formed when two or more elements chemically combine in whole # ratios
- During chemical reactions, atoms can combine separate rearrange but never created or destroyed
JJ Thomson
Major contribution
Name his model
What is this model missing
Discovered the electron
Cathode ray tube experiment
Missing nucleus, neutrons
Ernest Rutherford
Major contribution
Name model
Nucleus, atom is mostly empty space
Gold foil experiment
Neils Bohr
Name his model
His close version of current theory of the atom
Fusion
Where is it used
Combination of smaller nuclei into a larger one
The sun
Fission
Nuclei splits form to two or more smaller nuclei fusion- combination of smaller nuclei
What is radioactivity
Process of particles being emmited from nucleus as result of nuclear instability
Half life
Amount of time required for a decaying substance the lose half original mass
Three types of radioactive decay symbol and matter or energy
Alpha matter 4/2 HE
Beta matter 0/-1 E
Gamma energy /|
