Atoms, Bonding, and the Periodic Table

Name three parts of an atom and their charges.

Where is each part located?Which part makes up most of

the mass? volume?

Valence Electrons and BondingValence electrons-those electrons that are in the highest energy level and held most loosely (8=stable)

Electron dot diagram (Lewis structure)-the symbol surrounded by dots

Chemical bond-force of attraction that holds two atoms together as a result of the rearrangement of electrons between them

Draw the electron dot diagram for H, Ca, Al, C, N, O, Cl, and Ne.

Periodic TablePeriods= rows (7)Families/groups=columns (18)Atomic number-the number of protons in the atoms nucleus(increases by 1 as you go across the table)

Noble gases(stable)-group 18 elements (8 valence electrons except helium)

Halogens-group 17 elements (7 valence electrons)

Alkali metals-group 1 elements (1 valence electron)

Ionic Bonds(transfer of electrons)

Ion-an atom or group of atoms with an electrical charge.

Ionic bond-the attraction between two oppositely charged atoms. Ex: NaCl (ionic compound)

What would the charge be on the Na atom and the Cl atom? What does a 2+ charge mean? What does a 2- charge mean?

Properties of Ionic compounds include: high melting points, crystalline shape, and electrical conductivity

Covalent Bonds (sharing of

electrons) The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons. If one atom has a stronger pull on the electrons it charge becomes slightly negative.

Atoms can share two pairs (double bond) or three pairs (triple bond) of electrons

Unequal sharing of electrons is called a polar bond(Ex: H2O) and equal sharing of electrons is called a nonpolar bond(Ex: CO2)