The Periodic Table
the periodic table is arranged based on this
atomic number
metalloids
elements with properties that fall between those of metals and nonmetals
Group
A column on the periodic table
mass number (atomic mass)
The sum of protons and neutrons in the nucleus of an atom
ductile
can be drawn into wires; a property of metals
Period
A horizontal row of elements in the periodic table
metals
Elements that are good conductors of electric current and heat.
nonmetals
Elements that are poor conductors of heat and electric current
Alkali metals
Group 1A on the PT, have 1 valence electron, very reactive
Aklakine Earth metals
Group 2A, 2 valence electrons, pretty reactive
Halogens
Group 7A, 7 valence electrons, most reactive group of nonmetals
Noble gases
Group 8A, 8 valence electrons, not reactive at all
conductor
a material that allows heat and electricity to pass through it; a property of metals
brittle
easily broken, not flexible; a characteristic of nonmetals
malleable
easy to shape or bend; a characteristic of metals
valence electrons
electrons in the outermost shell of an atom; these are the electrons involved in forming bonds
reactivity
how readily an element chemically combines with other elements
electrons
negatively charged subatomic particles that orbit the nucleus
atomic number
number of protons in an atom of an element
protons
positively charged subatomic particles
neutrons
the particles of the nucleus that have no charge