basic atomic structure Flashcards
atom
the smallest unit that has a unique identity.
parts on an atom
nucleus with protons and neutrons, charged electrons in the electron cloud, shells (energy levels).
protons
positively charged subatomic particle.
isotopes
atoms with the same number of protons and electrons, but different numbers of neutrons.
atomic mass (amu)
protons + neutrons in an atom’s nucleus.
determined by the percentage of each isotope found in nature for that particular atom.
shown as a decimal of PT
atomic number
number of protons in the nucleus of an atom
shown as an integer on PT
neutral atoms
equal number of protons and electrons (a charge of 0)
ions
atom or molecule with a positive or negative charge.
when sodium loses an electron, it becomes more positively charged (NA+)
when chlorine gains an electron in becomes more electronegative (Cl-)
periodic table
arranges from left to right by increasing atomic number (number of protons shown as an integer).
groups: vertical columns of elements with similar properties (same number of valence electrons).
periods: horizontal rows that indicate the outer most shell (orbitals) of an atom.
orbitals
an area around the nucleus where an electron is found 90% of the time.
s orbital: 2 electrons
p orbital: 6 electrons
d orbital: 10 electrons
f orbital: 14 electrons
atoms that do not react with other atoms because of stability are called
inert
metals
a substance that is a good conductor of electricity and heat, forms cations by loss of electrons, and yields basic oxides and hydroxides
anion
a negatively charged ion by gaining electrons
cation
positively charged ions by losing electrons
ionic bond
the bond between two oppositely charged ions
transfer of electrons
compound
a substance made of two or more elements
covalent bond
atoms that share electrons
