Unit 4 - Periodic Table

Dmitri Mendeleev

Organized elements by increasing atomic mass Predicted properties of undiscovered elements Some discrepancies

Henry Mosely

Organized elements by increasing atomic number

Periodic Table

Shows all known elements in the universe and organizes them by chemical properties

Key to the Periodic Table

Elements are organized on the table according to their atomic number

Atomic Number

Refers to how many protons an atom of that element has

Bohr Model of Hydrogen Atom

A model that describes the structure of a hydrogen atom

Wave Model

A model that describes the behavior of electrons as waves

Atomic Mass

Refers to the 'weight' of the atom

Valence Electrons

Electrons in the outer energy level of an atom

Rows

Called 'Periods'

Columns

Called 'Groups' or 'Families'

Properties of Metals

Good conductors of heat and electricity

Properties of Non-Metals

Poor conductors of heat and electricity

Sulfur

A non-metal element

Properties of Metalloids

Have properties of both metals and non-metals

Silicon

A metalloid element

Group 1: Alkali Metals

Have 1 valence electron

Group 2: Alkaline Earth Metals

Have 2 valence electrons

Groups 3 - 12: Transition Metals

Have 1-2 valence electrons

Lanthanide Series

Shiny reactive metals

Actinide Series

Radioactive and unstable

Group 17: Halogens

Have 7 valence electrons

Group 18: Noble Gases

Have 8 valence electrons (except He which has 2)

Periodic Law

When elements are arranged in increasing atomic number, elements with similar properties appear

at regular intervals.

Atomic Radius

size of atom

Ionization Energy

Energy Required to remove an electron from a neutral atom

Electronegativity

The tendency of an atom for a shared pair of electrons

Electron Affinity

The amount of energy released when an electron is added to a neutral atom

What is this?

Increasing Atomic Radius

What is this?

Increasing Ionization Energy

What is this?

Increasing Electronegativity

What is this

Increasing Electron Affinity

Ionic Radius

More Electrons, the larger it is.
n^-1 is larger than N

N is larger than N²