Where it all is

1856: John Newlands discovered that elements had repeating patterns of chemical and physical properties. LAW OF OCTAVES

1869: Dmitri Mendeleev arranged the first one based on Atomic Masses and the Law of Octaves

1913: Henry Moseley Arranged the Modern Periodic Table based on Atomic Number.

1950: Glenn Seaborg developed the f block.

Groups or Families◦ Columns that go up and down.◦ There are 18 Groups

Periods◦ Rows that go across◦ There are 7 Periods

Highly reactive Replace Hydrogen in Water All have 1 valence electron All are s1

Forms +1 ions

Very reactive Don’t replace Hydrogen in Water

◦ Readily burn in O2 when exposed to heat Calcium makes up your bones. Batteries get their name from this group Have 2 Valence electrons

◦ All are s2 – forms +2 ions

These are the common metals All have d orbitals filling Less reactive than other metals Copper, Silver, and Gold least reactive Forms various positive ions

Have 3 Valence electrons◦ All are s2 p1

◦ All form +3 ions except Boron which forms a –3 ion

One is a metalloid (Boron) The rest are all metals

Carbon family has 4 valence electrons All are s2 p2

Composed of:◦ one non-metal (Carbon)◦ Two metaloids (Silicon and Germanium◦ Two metals (Tin and Lead)

Carbon always forms 4 bonds◦ All known life based on Carbon

Computers function based on Silicon and Germanium’s unique properties◦ They conduct electricity but not heat

Lead and Tin are common metals◦ Used to be used a lot in food storage

All have 5 valence electrons◦ All are s2 p3

Composed of:◦ two nonmetals - Nitrogen and Phosphorous◦ Two metalloids – Arsenic and Antimony◦ One metal - Bismuth

Nitrogen:◦ makes up most of the atmosphere◦ Critical to plant and animal life◦ Forms strong bonds that are used in explosives

Phosphorous◦ Critical to plant and animal life

All have 6 valence electrons◦ All are s2 p4◦ Usually form 2 bonds

Form – 2 ions (except Polonium +2, +4 ions) Composed of:

◦ 3 nonmetals – Oxygen, Sulfur, Selenium◦ 1 metalloid – Tellerium◦ 1 metal - Polonium

All have 7 valence electrons◦ All are s2 p5◦ Forms 1 bond

Forms – 1 ions All are nonmetals Highly reactive

◦ Never found in nature as single atoms◦ When pure will form F2, Cl2, Br2, I2

All have 8 valence electrons◦ All are s2 p6◦ Rarely form bonds

Never form ions◦ Helium, Neon, Argon have never been found in a

compound◦ Krypton, Xenon, Radium can sometimes be forced

to form compounds – but these are very unstable

Called Rare Earths◦ They are rare on earth - Most are manmade

All are radioactive All elements greater then Uranium (92) are

manmade Some are used in medical research

METALS Left of Staircase Ductile Form positive ions Lose electrons Malleable Conduct electricity and heat Shiny

NON METALS Brittle Dull Do not conduct electricity Do not conduct heat Gain electrons Form negative ions Right of staircase

Metalloids Also called semimetals Mix properties of both Silicon conducts electricity (metal) but not

heat (nonmetal). Silicon is shiny (metal), but brittle

(nonmetal)

Chemical Properties Elements in the same group will have

similar chemical properties. Elements in the same group have the same

number and arrangement of valance electrons

Elements lose and gain electrons to achieve the Noble Gas configuration