The Periodic

TableTextbook Pages: 22-30

The Development of The Periodic Table

Dmitri Mendeleev (1834-1907)Russian ChemistDeveloped table according to increasing atomic massesSimilar elements arranged in same column“Father” of the Periodic Table

The Modern Periodic TablePeriodic Law:

When elements are arranged by atomic number, their chemical and physical properties recur periodically.

Describes the repeating nature of the properties of

the elements

T.P.S. QuestionThinkPairShare

What else can you tell me about the characteristics of the modern Periodic Table?

The Modern Periodic Table The Periodic Table is split up into:

1. Groups 2. Periods

Group: Vertical column in the Periodic Table Same number of valence electrons Similar chemical and physical properties Family

Period: Horizontal row in the Periodic Table Atomic number increases from left to right Period number is number of electron shells occupied by electrons As go across period, outer electron shell is being filled Energy level

3

4

The Modern Periodic TableGroup 1: Alkali Metals

Very reactive metalsGroup 2: Alkaline Earth MetalsGroups 3-11: Transition MetalsMetalloids

Properties between metals and non-metalsGroup 17: Halogens

Reactive non-metalsGroup 18: Noble Gases

Completely unreactive

Periodic Trends1. Atomic Radius

2. Ionization Energy

3. Electron Affinity

4. Electronegativity

Periodic Trends Definitions1. Atomic Radius

The distance from the center (nucleus) of an atom to the boundary within which the electrons spend 90% of their time (outer perimeter)

2. Ionization Energy The amount of energy required to remove the outermost electron from

an atoms or ion in the gaseous state (eliminate effect of nearby atoms) Equations:

A(g) + energy A+(g) + e− (first ionization)

A+(g) + energy A2+

(g) + e− (second ionization) ***Requires more energy

3. Electron Affinity The energy absorbed or released when an electron is added to a

neutral atom

4. Electronegativity An indicator of the relative ability of an atom to attract shared electrons