Atoms Flashcards
Atom
building block of all matter
Element
Any material that is made up of only one type of atom
Periodic table
a chart that lists all known elements
Chemical Symbol
A shorthand notation of an element
consisting of a single capital letter, or a capital letter and
one or two small (lower case) letters
Chemical Formula
A shorthand method representing the
composition of a compound through the use of chemical
symbols and subscripts
Nucleus
- center of an atom
What is the Nucleus made of
protons and neutrons
Protons
– positively charged, located in nucleus
Neutrons
– neutral charge, located in nucleus
Electrons
– negatively charged, located orbiting
around nucleus
Atomic number =
the number of protons
contained in the atomic nucleus
Mass Number
= total # of protons and neutrons an
atom contains
Isotopes:
Atoms of the same element but different
number of neutrons
Atomic Mass:
the total mass of an atom
A period is
a horizontal row (7
periods)
A group is
a vertical column (18
groups)
Metals:
shiny, opaque, good conductors, malleable, ductile, and solid
Nonmetals:
poor conductors, transparent, solid
nonmetals are neither malleable nor ductile, brittle, and shatter when hammered
Metalloids
6 of them: B, Si, Ge, As, Sn, Sb, Weak conductors of electricity
John Newlands-
“Law of Octave”. Every 1st and 8th elements and 2nd and 9th
elements have similar properties.
Lothar Meyer-
connection between atomic mass and elemental properties
Dmitri Mendeleev-
organized elements into first periodic table.
Henry Moseley-
“Periodic Law”- elements are arranged by increasing atomic
number.
Glen Seaborg-
organized the periodic table by creating the Lanthanide and
Actinide series.
