Buda Academic Chemistry: CH 6- Trends in the Periodic Table

Periodic Law

When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

Groups

vertical columns of the periodic table.

Periods

horizontal rows in the periodic table.

Representative Elements

Elements in the portion of the periodic table containing groups 1A to 7A.

Transition Elements

Group B elements on the periodic table that include transition metals and inner transition metals.

Metals

One of a class of elements that are good conductors of heat and electric current; Tend to be ductile, malleable, and shiny

Alkali Metals

The group 1A metals; more chemically reactive than alkaline earth metals.

Alkaline Earth Metals

The group 2A metals; harder and less reactive than alkali metals.

Transition Metal

D block elements

Inner Transition Metal

a type of group B element that is contained in the f-block of the periodic table and is characterized by a filled outermost orbital, and filled or partially filled 4f and 5f orbitals. AKA: Rare Earth Elements

Lantanide Series

Elements 58-71, located on the bottom of the periodic table, 4f

Actinide Series

Elements 90-103, located on the bottom of the periodic table, 5f

Nonmetals

In general, these are poor conductors of heat and electric current, most are gases, solids are brittle and dull, only 1 liquid (Br).

Halogens

Nonmetals of group 7A; these nonmetals are highly unstable and are extremely reactive group.

Noble Gases

Elements in group 8A of the periodic table, sometimes called inert gases because they rarely take part in a reaction.

Metalloid

Generally has properties that are similar to those of metals and nonmetals; In certain environments it may behave like a metal or nonmetal.

Valence electrons

electrons on the outermost principal energy level of an atom.

Ion

An atom or group of atoms that has a positive or negative charge, either more or less electrons than protons and neutrons.

Ionization energy

the amount of energy required to remove an electron from an atom.

Ionization Energy Decreases because of the increase of energy levels and the shielding effect

What is the Ionization Energy Group Trend?

Ionization Energy Increases because of the increase of protons pulling the energy levels closer

What is the Ionization Energy Period Trend?

Electronegativity

the tendency of an atom to attract electrons in the formation of an ionic bond.

Decreases in electronegativity

What is the electronegativity Group Tend?

Increases in electronegativity

What is the electronegativity Period trend?

Octet Rule

atoms will gain, share, or give up electrons to achieve the electron configuration of a noble gas. meaning 8 valence electrons.

Demitri Mendeleev

Russian chemist credited with coming up with first functional periodic table. He organized elements by properties and atomic masses. Also predicted properties of some elements that were yet to be discovered

Henry Moseley

Arranged the periodic table by atomic number instead of mass number

Chemical Activity Increases as you go down the group

What is a Metals Chemical Activity Trend for a GROUP?

Chemical Activity Decreases as you move across the period

What is the Metals Chemical Activity Trend for a PERIOD

Francium

What metal is the most active?

Decreases down a GROUP

Nonmetal Chemical Activity Trend for a GROUP

INCREASES across a PERIOD

Nonmetal Chemical Activity Trend for a PERIOD

Fluorine

What nonmetal is the most reactive?

Number of Valence Electrons

Elements in the same group have the same what?

Energy Level of the Valence electrons

Elements in the same period have the same what?

Periodic Trend

property of the elements that can be predicted from the arrangement of the periodic table

Atomic Radius

size of an atom

This increases moving down a group (As the number of electrons increase, the electrons are further away from the center of the atom)

What is the Atomic Radius Group Trend?

The Atomic Radius decreases across the period-as protons increase, more protons pull the same energy levels in closer

What is the Atomic Radius Period Trend?

Shielding Effect

the electrons of previous energy levels shields the pull of the nucleus on outer level electrons (increases going down and constant going across)

Ionic Radius

The size of an ion

No trend as you move from left to right

BUT

(Non-metals (Anions) are Larger than Metals (Cations))

Cations get smaller from left to right

Anions get smaller from left to right

What is the Ionic Radius Period Trend?

ionic radii tend to increase down a group

What is the Ionic Radius Group Trend?

Francium (Electronegativity)

What element has the lowest electronegativity?

Fluorine (electronegativity)

What element has the highest electronegativity?