Atoms and the Periodic Table

metals

on the left of the periodic table, good conductors of heat and electricity, malleable, shiny, tend to lose electrons when chemically changed

non-metals

right side of table, solid at room temp, some are gases at room temp, poor conductors of heat and electricity

Noble Gases

unreactive nonmetals that are colorless and odorless gases at room temperature, group 8A

Halogens

group 7A, nonmetals, very reactive, 7 valence electrons

Alkaline Earth Metals

group 2A

Alkali Metals

group 1A

Transition Metals

Groups 3-12, middle of periodic table

group

A column on the periodic table

period

A horizontal row of elements in the periodic table

isotope

atoms with the same number of protons, but diff number of neutrons

mass number

protons + neutrons

atomic number

Number of protons

orbital

A region of space around the nucleus where an electron is likely to be found. inside subshells

atomic mass

The average mass of all the isotopes of an element,

AMU

atomic mass unit

In order of increasing atomic number

How the periodic table is arranged

Elements within the same group

Similar physical and chemical properties

The halogens

Group 17

Noble gases

Group 18

Proton

Positively charged particle in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A tiny, negatively charged particle that moves around 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

Periodic table

A chart of all chemical elements currently known

Element

pure substance that consists entirely of one type of atom

atom

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

Average atomic mass

The weighted average of all of the naturally occurring isotopes of an element