Properties and Trends in the Periodic Table

By increasing atomic mass

By alphabetical order of their chemical symbols

By increasing atomic number

By their discovery date

Dull appearance

Brittle nature

Poor conductors of heat and electricity

Malleable and ductile

It increases

It decreases

It remains constant

It first increases then decreases

The same atomic number

The same number of protons

The same number of valence electrons

The same atomic mass

The atomic radius decreases, making it easier to gain electrons

The outermost electron is further from the nucleus and more easily lost

The number of valence electrons increases

They become less metallic in character

They are more reactive than alkali metals.

They typically have one valence electron.

They are softer than alkali metals.

They have higher melting points than alkali metals.

As primary components in nuclear fuels.

As catalysts for various reactions.

For filling balloons due to low density.

As semiconductors in computer chips.

Iron

Helium

Silicon

Chlorine

Reactivity increases due to increasing electron affinity.

Reactivity decreases due to increasing atomic radius and decreasing electron affinity.

Reactivity remains constant as they all have 7 valence electrons.

Reactivity increases due to decreasing atomic radius.

They are highly reactive and form many compounds.

They have full valence electron shells and are unreactive.

They are colored gases with high boiling points.

They are good conductors of heat and electricity.