Periodic Table Flashcards
what was Dalton’s theory
the atom was a solid sphere that was indestructible and all atoms of the same element were identical
what was JJ Thomson’s theory called
the plum pudding model
findings of Rutherford’s gold foil experiment
most particles passed straight through showing atom consisted of mainly empty space
few particles were deflected
few bounced back
structure of an atom
consists of protons, neutrons and electrons
atomic number
number of protons
mass number
number of protons and neutrons
what are isotopes
different atoms of the same element that have the same number of protons but different number of neutrons in their nuclei
why isotopes have similar chemical properties
they have the same number of electrons in their outer shell
2 ways isotopes are similar
same number protons in their nuclei
similar chemical properties
2 ways isotopes are different
different physical properties
different number of neutrons in their nuclei
what is relative atomic mass
average mass of an atom of an element relative ti 1/12th of the mass of an atom of carbon-12
how did Mendeleev arrange his elements
in order of increasing relative atomic mass
why did Mendeleev leave gaps
he assumed these elements had not been discovered yet and predicted the properties of some missing elements
3 similarities between Mendeleev’s table and modern table
elements put into groups
elements put into periods
elements with similar chemical properties put in same groups
what are group 1 metals called
the Alkali metals
what are group 7 elements called
the halogens
what are group 0 elements called
the noble gases