The nature of matter Flashcards
atom
basic unit of matter
3 subatomic particles
proton, neutrons, electrons
proton
positively charged in the nucleus
neutrons
found in the nucleus; has no charge
electrons
negatively charged; outside the nucleus
valence electrons
electrons on the outermost shell
atomic number
tells you the number of protons in the atom
protons are equal to
the number of electrons
mass number is also called
the atomic mass
mass number
the number of protons and neutrons in an atom
to find neutrons, subtract …
the atomic number from the atomic mass
atomic structure
shows the number of protons, neutrons, & electrons in an atom
dot structure
only shows the number of valence electrons
how many electrons are in the first shell
2
how many electrons are in the 2nd shell
8
how many electrons are in the third shell
8
isotope
atoms of the same element with a different number of neutrons
compounds
2 or more elements chemically combined in fixed proportions
chemical bond
force that holds atoms together
atoms bond to become …
stable
stable atoms
have a full outer shell
valence electrons …
gain, loose, and share electrons
ion
a charged atom
ions have more or less electrons…
than it does protons
what charge does an ion have
either negative or positive
groups 1, 2, & 3 on the periodic table are…
cations
cations (metal pr nonmetal)
metals
A cation’s job is to …
give away electrons
how many electrons does it have to give away to be complete
as many as it takes for a full outer shell
groups 5,6, & 7 on the periodic table are
anions
an anion’s job is to
take electrons
ionic bond
the transfer of electrons between atoms
an ionic bond happens between
an anion and a cation
ionic bond: givers give electrons to
takers (anions)
what is the point of an ionic bond
to create stable atoms & form compounds