Periodic Table #1

Periodic table

A chart of all chemical elements currently known, organized by their properties.

Neutron

A subatomic particle that is neutral and that is found in the nucleus of an atom

Electron

A tiny, negatively charged particle that moves around the nucleus of an atom.

Group 1

Alkali metals.

Group 2

Alkaline earth metals

metalloids

Found along the 'staircase'. Have properties of both metals and nonmetals

Halogen

Means "salt producer" also group 17

Proton

Positively charged particle in the nucleus of an atom

Atomic Number

The number of protons in the nucleus of an atom of an element

Mass Number

The total number of protons and neutrons in an atom's nucleus

Radioactive isotopes

are unstable

nonmetals

brittle , dull, poor conductors of heat and electricity

Mendeleev

created one of the first periodic tables by using atomic mass

Bohr

discovered that electrons follow an orbit/shell

Noble gases

elements in group 18 that have complete outer shells

alkaline earth metals

hard, grey-white, good conductors of electricity, calcium and magnesium are examples

periods

horizontal rows on the periodic table

Period number

is the amount of energy levels (shells) an atom has

Transition metals

most are hard and shiny, less reactive, examples are iron, copper, nickel and gold

Element

pure substance that consists entirely of one type of atom

Valence electrons

subatomic particles that are located the farthest away from the nucleus- determine bonding

lanthanides

the first period below the periodic table, they are mixed with more common metals to form alloys

actinides

the period below lanthanides, very unstable

Isotope

the protons remain the same as the atomic number, but the neutrons do not

atom

the smallest unit of an element that maintains the properties of that element

Groups 3-12

transition metals

groups

vertical columns on the periodic table that have common properties

alkali metals

very reactive, not found alone in nature, react violently with water