What is the periodic table?

The Periodic Table Created by Dmitri Mendeleev Considered one of the greatest discoveries in science Structures and properties of elements are periodic – occurring repeatedly or at regular intervals

Current Table 117 elements First 94 naturally occur Remaining 23 not found naturally on Earth – Can be artificially created – Americium – smoke detectors Left to right – metals, metalloids, nonmetals Nearly 80% are metals – shiny, bendable, conductors of heat, electricity Nonmetals – dull, brittle, poor conductors Metalloids – between metal and nonmetal

How to Read the Table Chemical name Chemical symbol – abbreviation – Can be based on its Latin name Atomic number – number of protons, top number of square – Increase in order from left to right, top to bottom Atomic weight – number of protons + neutrons, number at bottom of square – Number of neutrons = atomic weight – atomic number

Periods and Groups Periods – a row in the periodic table – Same number of atomic shells (cluster of orbitals) – 1 to 7 (number of atomic shells) First shell closest to nucleus Shells layer like an onion Groups – column in the periodic table – Same number of outer-shell electrons – Tells how the element will combine with other elements

Day 1 1. the number of protons, neutrons, and electrons in an atom of an element 2. how electrons are arranged in orbitals 3. which elements are likely to react and combine with each other

Day 2 A 1. shiny 2. can bend without breaking 3. good conductors of electricity B 1. boron, silicon, germanium, arsenic, antimony, tellurium, polonium, astatine 2. aluminum 3. hydrogen

Day 3 1. Cl, 17, 18, Ca, 20, 20, Fe, 26, 30, Pb, 82, 125, 82

Day 4 A Mg, Al, Si, P, S, Cl, Ar 3. H, Li, K, Rb, Cs, Fr B. The number of outer-shell electrons determines how an element will combine with other elements.