Periodic Tableand Stability in Bonding

Pages 554 - 562

Mendeleev came up with the first periodic table. It was based on the atomic masses, instead of atomic numbers.

This is Hydrogen, upper left on the periodic table. Not happy, for it has but a single electron in its outer shell.

This is Helium. It is upper right on the periodic table. It is very happy (feeling Noble), for its outer shell is full. It will allow no more electrons in, nor will it allow any electrons to leave, without paying a great price. It is stable.

This is Lithium. It wants to join the party, but it cannot, for it needs a full outer shell, and except for Helium, all outer shells need eight electrons. This makes Lithium “unstable”.

This is Beryllium. It is also “unstable”.

This is Boron. It is also “unstable”.

This is Carbon. It is also “unstable”.

This is Nitrogen. It is also “unstable”.

This is Oxygen. It is also “unstable”.

This is Fluorine. It is also “unstable”.

This is Neon. It is “stable”, because it has an filled outer shell.

This is Neon. It is “stable”, because it has an filled outer shell.

This is hard to draw, however, so we just draw

NeThis will indicate a Neon atom, with a filled outer shell. We only draw the outer shells.

NeThis will indicate a Neon atom, with a filled outer shell. We only draw the outer shells.

Cl This will indicate a Chlorine atom, with seven electrons in its outer shell. We only draw the outer shells.

-1

NeThis will indicate a Neon atom, with a filled outer shell. We only draw the outer shells.

Cl This will indicate a Chlorine atom, with seven electrons in its outer shell. We only draw the outer shells.

Cl This will indicate a Chlorine atom, with its normal outer shell filled. We only draw the outer shells. But now we have to show that it has too many electrons.

-1

NeThis will indicate a Neon atom, with a filled outer shell. We only draw the outer shells.

Cl This will indicate a Chlorine atom, with seven electrons in its outer shell. We only draw the outer shells.

Cl This will indicate a Chlorine atom, with its normal outer shell filled. We only draw the outer shells. But now we have to show that it has too many electrons.

-1

Na This will indicate a Chlorine atom, with its normal outer shell having no electrons. We only draw the outer shells. But now we have to show that it has too many electrons.

+1

Nobel Gases Will Always Have Full Outer Shells

GROUPS ALWAYS GO UP AND DOWN

PERIODS GO LEFT AND RIGHT

AS YOU GO ACCOSS GROUPS, YOU ADD ELECTRONS IN THE SAME ELECTRON SHELL.

AS YOU GO DOWN THE PERIODS, YOU ADD SHELLS OF ELECTRONS TO THE ATOM.

Metals are on the left and bottom of the chart.

Nonmetals are on the right of the chart.

Metalloids are where the two meet.

Nobel Gases are on the end, with filled shells.

The only reason these are down here, is so the table does not get too long to fit in a book, or on a wall.