The Periodic Table

Alkali metals Highly reactive metals

in group 1A of the periodic table

Alkaline earth metals Fairly

reactive metals in group 2A of the periodic

table

Transition metals Those elements

found in the d block of the periodic table

whose properties tend to be less

predictable based simply on their position

in the table

Halogens families Highly

reactive nonmetals in group 7A of

the periodic table

Noble gases The group 8A

elements, which are largely

unreactive (inert) due to their stable

filled p orbitals

The Periodic Table

Atomic radii A measure of the size of an atom

Ionic radii A measure of the size of an atoms ion in a crystal lattice form

Electronegativity The ability of an atom to attract electrons to itself

Ionization energy The energy required to remove an electron from an atom or ion in its gaseous state

Knowing the Periodic Table

Rows are referred to as periods

Columns are referred to as families or groups

Elements within a group generally have similar properties

When elements are arranged in order of increasing atomic number, there are recurring physical and chemical properties Periodic law

States of Matter at Room Temperature

Development of the Periodic Table

The number of known elements drastically increased in the early 1800s

In 1869, Dmitri Mendeleev from Russia and Lothar Meyer form Germany published classification systems

Mendeleev is given credit for organizing elements into the periodic table

Development Cont.

The periodic table is an arrangement of elements in which they are separated into groups based on repeating properties

Mendeleev arranged the elements in order of increasing mass (there were some exceptions Ex. Te and I)

It was later realized that arranging by properties, rather than mass was more accurate

Mendeleev left gaps for undiscovered elements, but accurately predicted their properties

Modern Periodic TableIn the early 1900’s Henry Moseley determine atomic numbers of each known element

The modern table is arranged based on increasing atomic numbers

Each period on the periodic table corresponds to a principal energy level

Elements with similar chemical and physical properties end up in the same column

Main Chemical Families

Alkali Metals

Alkaline Earth Metals

Transition Metals

Halogens

Noble gases

Properties of Alkali Metals (Group 1)

Have metallic properties of metalsShiny luster, malleability, high thermal and electrical conductivity

Soft solids at room temperature, low melting points and densities

Very reactive! (Especially with water)

Found as compounds in nature, never as free elements

Lose an electron when they react, thus have a +1 oxidation state

Properties of Alkaline Earth Metals (Group 2)

Soft metals

Very reactive! (Less reactive than alkali metals)

All except beryllium (Be) react with water

Most occur naturally only in compounds

When reacted, they give up 2 electrons and have a +2 oxidation state

Properties of Transition Metals (Groups 3-12)

Most transition metals have common metallic characteristics with other elements in their families ; except zinc (Zn), cadmium (Cd), and mercury (Hg)

Can exist in several common oxidation states

Are likely to form complexes with unbalanced charges and excessive electrons

Properties of Halogens (Group 17)

All halogens are nonmetals

Generally poor conductors of heat and electricity

Are not all found in the same state of matterThe only family with all 3 states of matter

At room temperature, fluorine (F) and chlorine (Cl) are gases. Bromine (Br) is a liquid. Iodine (I) and astatine (At) are solids.

Very reactive (will even react with glass!)

Halogens are commonly found as diatomic molecules (F2, Cl2)

Gain an electron when reacted; oxidation state of -1

Properties of Noble Gases

All gases at room temperature

Odorless and colorless

Very low reactivity

Exist as unbound elements in nature

Referred to as inert (nonreactive)

Trends of Atomic Radii

Size of atoms is expressed as the atomic radius

Atomic radii generally decrease from left to right across a period and increase from top to bottom of a group

Principal quantum number (n) of outer-level electrons increases by one from period to period

Ex. Elements in period 1, n=1. For period 2, n=2, and so onAs n increases down a family, the average position of outer-level electrons is farther from the nucleus

As a result, atoms are LARGER

Trends of Ionic RadiiIon atom or group of atoms with a charge

Cation atoms that have lost 1 or more e- and have a + charge

Cations are smaller in radius because they have lost e-

Ex. Ca2+ is smaller than Ca because it has lost 2 e-

Anion atoms that have gained 1 or more e-

Anions are larger because they have gained e-

Ex. Br- is larger than Br because it has one more e- orbiting

Trends of anions and cations are similar to that of their neutral atomic radii

Electronegativity TrendNumber of protons and the principal

quantum number influence electronegativity

Generally, electronegativity increases from left to right across a period (because the # of p+ increases)

It generally decreases from top to bottom of a group (due to outer energy level e- being farther from the nucleus

Ionization Energy TrendIn the event of multiple e- being removed

from an atom, there are different ionization energies corresponding to each e- removed

The energy required to remove the first e- is referred to as the “first ionization energy”

Generally, ionization energy increases from left to right across a period and decreases from top to bottom within a family

Ionization Energy Cont.

Depends on the force of attraction the nucleus exerts on the e-

Also depends on # of p+ and distance of e- from the nucleus

The more p+ force, the more difficult to remove an e-

Atomic Radii Practice

Arrange the following elements in order of increasing atomic radii

SodiumIronPotassiumSulfurPhosphorus

Ionic Radii Practice

Arrange the following ion in decreasing order of ionic radii

Mg2+

F-

Cu2+

Li+

O-

Electronegativity Practice

Which of the following atoms is more electronegative? Which is less?

CalciumChlorine

Explain why you chose ___ as more electronegative than ___.

Ionizing Energy Practice

Do metals or non-metals have a higher ionizing energy?

List the following elements in order of increasing ionizing energy

AuCoPd