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