Periodic Table

Periodic Table

Pearl Lian Period 1

Group 14: Carbon GroupValence electrons: 4Reactivity: varies

Metals

Nonmetals

Metalloids

PERIODIC LAW

The law states thatthe repeatingchemical and physical propertiesof elements relate to and depend onelements'atomicnumbers.

Location: Left of the zigzag lineProperties: Shiny, ductile, malleable, good conductors of electricity and heat• Solid at room temperture• Have few electrons in their most outside clouds

Location: Bordered the zigzag lineProperties: Hard, very brittle, good conductors of electricityat high temperture• Have about half of a completeset of electrons in their most outside clouds

Location: Right of the zigzag lineProperties: Dull, not ductile or malleable, and cannot conduct electricity and heat• More than one half of them are gases at room temperture• Have an almost complete set of electrons in their most outside clouds

Dmitri Mendeleev, a Russian chemist of 19 century, was the first man to discover a pattern, which was periodic, to the elements in1869, and he organized elements in their atomic mass. Thus, his table of elements became known as the periodic table of elements. Mendeleev correctly predicted that the gaps of the pattern will be filled in by elements yet to be found.

Henry Moseley, a British scientist of 20th century, determineed the atomic number, which is thenumber of protons in an atom. In 1914, he rearranged the elements by their atomic number and they fit thepattern in Mendeleev's periodic table.

Group 1: Alkali MetalsValence electrons: 1Reactivity: very reactiveOther properties: softness; color of silver; low density

Group 2: Alkaline-Earth MetalsValence electrons: 2Reactivity: slightly less reactive than alkali metalsOther properties: color of silver; density higher than density of alkali metals

Group 3-12: Transition MetalsValence electrons: 1 or 2Reactivity: less reactive than alkaline-earth metalsOther properties: shinieness; good conductor of heat and electricity; density and melting points higher than most elements in Groups 1 and 2

Group 13: Boron GroupValence electrons: 3Reactivity: reactive

1

5

Group 13: Boron GroupValence electrons: 3Reactivity: reactive

Group 14: Carbon GroupValence electrons: 4Reactivity: varies

1

2

3

Group 15: Nitrogen GroupValence electrons: 5Reactivity: varies

2

1

2

Group 14: Carbon GroupValence electrons: 4Reactivity: varies

Group 16: Oxygen GroupValence electrons: 6Reactivity: reactiveOther Properties: solids at room temperature(excepet oxygen)

2

3

1

Group 14: Carbon GroupValence electrons: 4Reactivity: varies

Group 17: HalogensValence electrons: 7Reactivity: very reactiveOther properties: poor conductors of electricity; reactive with alkali metals; always in combined form in nature

Group 18: Noble GsesValence electrons: 8 (except helium)Reactivity: unreactiveOther properties: colorless, odorless gases at room temperature

period-a horizontal rowgroup-a vertical columnvalence electrons-electrons in the most outside clouds