MET7 - Periodic Table

Periodic Table

and Periodic trends

Blocks

Representative elements

Periods

Groups or families

Structure of the periodic table

Atomic mass

Chemical symbol

Chemical name

Atomic number

Periodic table

Organizes all the chemical elements existing till now.

VIIIA

VIIA

VIA

VA

IVA

IIIA

IIB

IB

VIIIB

VIIB

VIB

VB

IVB

IIIB

IIA

IA

Synthetic

Metaloids

Noble Gases

Nonmetals

Metals

Classification of the elements

Periodic trends

Periodic table

Electronegativity

Tendency of an atom to atract and form bonds with electrons.

Ionization energy

Energy needed to remove an electron from an atom.

Atomic Radius

Distance from the nucleus to the most external energy shell of the atom

Metallic and Nonmetallic character

Classification of the elements according to their physical and chemical properties

Metaloids

They have intermediate properties between metals and non-metals

• Can form covalent and ionic bonds
• Their luster vary between the elements.
• Semiconductors of heat and electricity.
• Can form alloys with other metals.

Ionization energy

Ionization energy increases when there are more electrons in the most external energy shell. Elements with larger electronegativity tend to have higher ionization energy. Elements with lower electronegativity tend to have lower ionization energy.

Synthetic elements

Do not exist in nature.

• Created in laboratories.
• All elements above Uranium (U) are synthetic.
• These elements are highly unstable, therefore, radioactive.
• Their properties are hard to study due to their short lives.
• Elements from 93-108 have been determined as metals. From 109-118 has not been possible to determine their nature.

Atomic radius

The radius increases from left to right and from top to bottom. When an ion gains electrons (anion) its atomic radius increases, if it loses electrons (cation) the atomic radius decreases.

The rows of the periodic table. There are 7 periods.

Periods

• Each period represent an energy shell.
• The valence electrons in the outermost shell increases by one.
• The metalic character decreases from left to right
• The atomic radius of the elements decreases from left to right.
• The electronegativity increases from left to right.

• Same valence electrons in the outermost electron shell.
• Similar chemical reactivity.
• The atomic radius increases from top to bottom.
• Similar tendencies in their physical properties.

Groups or families

The columns of the periodic table. The elements in each group share similar properties and characteristics like:

The metallic character transitions into nonmetallic from left to right in the periodic table.

• Poor heat and electricity conductivity.
• No metalic luster
• Britle
• Solid, liquid or gas state at room temperature
• Tendency to form anions.

• Good heat and electricity conductivity.
• Metalic luster
• Maleability and ductility
• Solid state at room temperature (except Mercury)
• Tendency to form cations.

Nonmetalic character

Metalic and Nonmetalic character

Metalic character

Blocks

Called like this because of the subshells that are the last ones to be filled.

Nonmetals

• Forms anions and tend to gain electrons.
• Poor heat and electric conductors.
• They are brittle.
• Non-lustrous
• Found as liquids, solids and gases.
• Variable melting and boiling points (generally lower than metals)

Transition metals

Metals

• Form cations and tend to lose electrons
• Have bright luster.
• Conduct heat and electricity.
• Ductile and malleable
• High melting and boiling points.
• Form alloys.
• Solid (except mercury).

Noble gases

• Complete set of electrons in their outermost energy shell.
• Low reactivity.
• Low melting and boiling points.
• Gases at environmental temperature.

Electronegativity

The higher the electronegativity, the greater the tendency to attract electrons. Influences the polarity of a chemical bond (e.g. ionic bond or polar covalent bond) The electronegativity decreases when the atomic radius is larger

• Fluorine: 3.98
• Francium: 0.7

Representative elements

Elements from group A: I, II, III, IV, V, VI, VII, VII. (1,2, 13-18)

• Found in s- and p-block of the periodic table.
• Formed by metals and nonmetals
• Most abundant elements on Earth.
• Form different compouds, and are greatly used in the industry and technology.