Prelims - Lec 3 - The Periodic Table of Elements

Periodic table

A tabular display of the chemical elements, which are arranged by atomic number, electron configuration, and recurring chemical properties.

Dmitri Mendeleev

The Periodic Table of Elements was introduced by

1869

When was The Periodic Table of Elements introduced?

63 elements

Initial number of elements in the periodic table.

118

As of 2019, there are \# known elements

Oganeeson

Element 118

Atomic number (Z)

The no. of protons in the nucleus of an atom that determines the chemical properties of an element and its place in the periodic table.

Atomic mass (A)

It is equivalent to no. of nucleons or to the average number allowing for the relative abundance of different isotopes.

7

\# of periods in the periodic table

Period

It tells the energy level of the element’s valence electron/s. It tells the shell being occupied by the outermost shell.

Blocks

A set of elements unified by the atomic orbitals their valence electrons lie in (s, d, p, f).

Alkali Metals

All Group 1 elements but hydrogen. It extremely reactive and highly flammable in water.

Alkaline-Earth Metals

All Group 2 elements. It is highly reactive (but slower than alkali) and is rarely found alone in nature.

Lanthanides

Group 3 Bottom Table elements. They are silvery white metals and tarnishes easily on contact with air.

Actinides

Group 3 Bottom Table elements. All radioactive elements.

Thorium & Uranium

Also called inner transition metals

Actinides that only occur naturally on Earth.

Inner Transition Metals

Other term for Actinides.

Transition Metals

All elements from Group 3-12. They are, shiny but malleable metals. They are good conductors.

Post-Transition Metals

All elements from Group 13-17. They possess classic characteristics of transition metals but tend to be softer and conduct more poorly.

Metalloids

Elements from Group 13-17. Represents transition from metals to nonmetals. It is used as semiconductors.

Semi-Metals / Poor Metals

Other term for Metalloids.

Non-Metal Groups

Elements from Group 14-16 including Hydrogen.

Halogen

Group 17 elements that are highly reactive. It is combined with alkaline to form salts.

Noble Gases

Group 18 elements. All elements in group 1 except Hydrogen and is extremely reactive. Also highly flammable in water.

↑ Atomic Radius

↑ Shell, ↓ Periodic Table

↓ Atomic Radius

↑ Protons, ←→ Periodic Table

Ionization Energy

Energy required to remove an electron from atom.

↑ Ionization Energy

↑→ Periodic Table

Radioactive Elements

Elements with no stable isotopes.