Write the name for the following chemical symbols? 1.Be beryllium 2.Ca calcium 3.Si silicon 4.Al aluminum 5.Ar argon 6.Ni nickel Write the chemical symbol for the following elements? 7. Gold Au 8. Silver Ag 9. Tin Sn 10. Helium He 11. Carbon C 12. Fluorine F

The Periodic Table Elements are organized based on their physical and chemical properties in the periodic table:  Elements listed in rows by increasing number of atomic number  Rows are called periods  Columns are called families or groups  Elements with similar properties would line up in vertical columns

Periods Families or groups

Dmitri Mendeleev  Godfather of the periodic table  1st guy smart enough to record important properties of known metals and find a way to organize it  Also considered elements that had not been discovered yet.

VIDEO On Dmitri Mendeleev

The Numbers on the Periodic Table Copy this into your notes so that you know what the numbers mean when you look at the periodic table.

The #s on the Periodic Table  Atomic number: number of protons in the nucleus of each atom of an element (always a whole #)  Atomic mass: mass of an average atom of an element; measured in atomic mass unit (amu) and written as a decimal  Mass number: a count of the number of particles in an atom’s nucleus Mass number = (number of protons) + (number of neutrons)

How to find the number of protons, electrons and neutrons in an element? The number of protons is…  Atomic number = # of protons The number of electrons is…  Atoms have a neutral charge so they must have an equal number of protons and electrons  THEREFORE…atomic number = # of protons = # of electrons

The number of neutrons is…  Mass number = (number of protons) + (number of neutrons)  Mass number is not given in the periodic table BUT...all you need to do is round the atomic mass to the nearest whole number  # neutrons = mass number - # protons

Ex. Find the # of protons, electrons and neutrons for the following elements.  Atomic number is 36  # of protons = 36  # of electrons = 36  Atomic mass =  Mass number = 84  # neutrons = Mass number - # of protons  # of neutrons =  # of neutrons = 48

ElementAtomic #Atomic mass Mass number Number of protons Number of electron s Number of neutrons Sn = 69 Cu = 35 He = 2

Ions  Ion: a charged atom  Ion charge: an electric charge that forms when an atom gains or loses electrons  If an atom loses electron(s)  positive ion (lost negative charge)  If an atom gains electron(s)  negative ion (gains negative charge)