The Periodic Table

Dmitri Mendeleev, increasing atomic mass

Henry Moseley, atomic number

John Dalton, atomic weight

Marie Curie, radioactivity

He rearranged the elements based on their atomic number.

He grouped elements with similar properties.

He predicted the existence of undiscovered elements.

He published the first periodic table.

Same number of valence electrons

Same atomic mass

Same number of energy levels

Same physical state

They are hard and brittle

They have one valence electron

They are soft and silvery colored

They are the most reactive group of metals

Lithium

Potassium

Magnesium

Rubidium

They are less reactive, harder, and denser

They have one valence electron

They are soft and silvery colored

They form +1 ions

High melting and boiling points

Electrical and thermal conductors

Low densities

Malleable and ductile

Scandium

Iron

Copper

Sodium

Boron

Gallium

Iron

Aluminum

Germanium

Lead

Tin

Carbon

They all have 5 valence electrons.

Nitrogen is a non-metal.

Bismuth is a good conductor of heat.

Arsenic and antimony are metalloids.

Highly reactive

Full valence shell

Gases at room temperature

Low boiling points