chapt 8 : atoms and molecules Flashcards
what does proton also mean?
number of electron and atomic number
what does relative atomic mass also mean
mass number and nucleuon number
what does proton + neutron =
relative atomic mass
how to find neutron
relative atomic mass - proton
how to find proton
p=e
relative atomic mass - neutron
are proton number unique?
yes
are relative atomic mass number unique ?
no
how many electron can the first shell hold?
2 electrons
how many electrons can the 2nd shell and the subsequent shells hold?
8 electrons
what is in the nucleus ?
protons and neutrons
what does it mean when an atom has maximum amount of valence electrons?
it means that the atom is very stable an unreactive, it has a stable electronic configuration
what are ions
ions are charged particles. they are formed when an atom loses or gains electrons
what is a positive ions
an atom is changed into a positive ion when it loses electrons.
metals, with 1,2,3 valence electrons tend to lose electrons to form stable noble gas configuration
what is negative ion
an atom is changed into a negative ion when it gains electrons.
non-metals, with 5,6,7 valence electrons tend to gain electrons to form stable noble gas configuration
electrons in the same period contains the same number of electron shells
SHELLS
