The Periodic Table

Horizontal Rows are called Periods. Elements in the same period have the same number of energy

levels for ground state electron configurations.

Vertical Rows are called Families or Groups. Families have the same valance electron

configurations.

Family 1

Alkali Metals

Family 1 Most active of all the metals One valance electron in outer most energy level.

(ns1: Li – 1s22s1, Na – 1s22s22p63s1) Lose the one valance electron when forming

chemical bonds. Form +1 ions. All atoms “want to have an octet of valance

electron so they will gain lose or share electrons to get to this “magic number.”

Family 2

Alkaline Earth Metals

Family 2.

Second most active of the metals.

Two valance electrons (ns2: Be – 1s22s2, Mg – 1s22s22p63s2)

Lose both valance electrons when forming chemical bonds.

Form +2 ions.

Family 17

Halogens

Family 17.

Most active of the nonmetals.

7 valance electrons (ns2np5: F – 1s22s22p5, Cl – 1s22s22p63s23p5)

Gain 1 electron to obtain octet.

Form -1 ions.

Halogens is Greek for salt former; they form salts when reacting with metals.

Family 18

Noble Gases – Inert Gases

Family 18. Most inactive of all elements. Do not normally form compounds. 8 valance electrons (ns2np6: Ne – 1s22s22p6,

Ar – 1s22s22p63s23p6) A perfect octet of electrons so they do not gain

or lose electrons to form compounds. Helium is only 1s2, but it still does not form

compounds because the 1st energy level is filled with only 2 electrons.

Group B Elements

Transition Metals

Family 3 – Family 12 Less active than alkali or alkaline earth metals. One or two valance electrons. All transition

metals have ns1 or ns2 valance electron structures.

They have (n-1)d1 – (n-1)d10. They have oxidations (ion charges) of +1

through +7. Transition metals do not obtain octets because

they have “d” electrons involved in bonding.

Inner-transition Metals

Stair Step Line: Divides Metals and Nonmetals

Metalloids

Metalloids

Have properties of both metals and nonmetals.

Semiconductors; metals are conductors and nonmetals are nonconductors.

If element is on the metal side treat as a metal; if it is on the nonmetal side treat as a nonmetal.

Boron Family

Family 13

Boron – metalloid

Aluminum and rest are metals.

3 valance electrons.

ns2np1

+3 ion charge

Carbon Family

Family 14

Carbon – nonmetal

Silicon and germanium are metalloids.

Tin and lead are metals.

4 valance electrons.

ns2np2

Carbon and silicon can be +4 or -4 or it can share electrons to form bonds.

Tin and lead can be +2 or +4.

Nitrogen Family

Family 15

Nitrogen and phosphorus are nonmetals.

Arsenic and antimony are metalloids.

Bismuth is a metal.

5 valance electrons.

ns2np3

Nitrogen and phosphorus are usually +3.

Bismuth and antimony are +3 or +5.

Oxygen Family

Family 16

Oxygen, sulfur and selenium are nonmetals.

Tellurium and polonium are metalloids.

6 valance electrons.

ns2np4

Oxygen and sulfur are usually -2.

S, P, D, F Block Elements

Noble Gas Configurations

History and Periodic Properties of the Periodic Table

Objective: explain the use of chemical and physical properties in the historical development of the Periodic Table.

Objective: use the Periodic Table to identify and explain periodic trends, including atomic and ionic radii, electronegativity, and ionization energy.

The Father of the Periodic Table

Dmitri Mendeleev’s Periodic Table

History of the Periodic Table

John Newlands: 1864

He proposed an organization scheme for the elements.

Newlands noticed that when the elements were arranged in order of increasing atomic mass, their properties repeated every eight elements.

This pattern is “periodic” because it repeats at regular intervals.

History: Part II

Dmitri Mendeleev: 1869

He noticed the same “periodic” pattern as Newlands.

By arranging the elements in order of increasing atomic mass into columns with similar properties Mendeleev credited the first periodic table.

He predicted the properties of scandium, gallium, and germanium.

History: Part III

Mendeleev’s table had problems.

When new elements were discovered it was found that the order was not correct.

Henry Moseley: 1913

Mosley discovered that each element had a unique number of protons.

He proposed that the periodic table be arranged in order on increasing atomic number.

The Periodic Law

There is a periodic repetition of chemical and physical properties of the elements when they are arranged in order of increasing atomic number.

The properties of the elements are related to their atomic numbers and their location on the periodic table.

This repetition can be seen in both families and periods.

Atomic Radius

Atomic Radius

Atomic radius is the “size” of an atom.

Atomic radius is half the distance between the nuclei of two atoms.

Atoms with a large atomic radius will be easy to remove an electron from; these are usually the metals.

Atoms with a small radius are harder to remove an electron from; these are usually the nonmetals.

Largest radius = francium

Smallest radius = helium

Ionization Energy

Ionization energy is the energy required to remove one electron from an atom.

Elements with low ionization energies tend to lose electrons and form positive ions.

Metals have low ionization energies, nonmetals are high.

Electronegativity Indicates the relative ability of an atom to

attract electrons in a chemical bond.