atomic structure (pg 4-19) Flashcards
the five names of groups on the periodic table
group 1- alkali metals group 2- alkaline earth metals transition metals group 7- halogens group 0- noble gases
law of conservation
the total mass of the products formed in a reaction is equal to the total mass of the reactants
when is the law of conservation broken?
in reactions involving gases with an open container. atoms can escape into the air.
balance H2 + O2 –> H*2 O
2H2 + O2 –> 2H*2 O
John Dalton
- tiny, hard spheres
- atoms could not be divided or split
- building blocks of nature
J.J Thompson
- discovered the electron
- did experiments with cathode ray tubes
- plum pudding model
Rutherford
- small positive nucleus
- atom is mostly empty space
- gold foil experiment
- positive charge concentrated in a tiny spot in the center of the atom
- electrons orbiting around a nucleus
Niels Bohr
- electrons orbiting the nucleus at set distance, fixed energy level
- energy given to electrons at low energy level
James Chadwick
nucleus contains protons and neutrons
why do atoms have no charge?
because there are the same amount of electrons(-1) and protons(+)
Atomic number
number of protons (=number of electrons)
Mass number
number of protons + neutrons
how to work out number of neutrons
mass number - atomic number
ion
a charged atom, by having a different number of electrons to protons
Isotopes
atoms of the same element with different numbers of neutrons but same number of protons
what do shells represent
a different energy level
what does the number of electrons in the outermost shell of an element determine?
the way in which that element reacts
