Periodic Table

Atomic Number

Atomic Number refers to the amount of protons an atom has.

Elements are organized by their atomic number

No two elements have the same amount of protons

Atomic Mass

Atomic Mass refers to the weight of an atom it is calculated by adding the number of protons and neutrons together

Group = Column

Elements in a group share similar characteristics and trends in physical & chemical properties

Group 1: Alkali Metals

The metals themselves are not alkaline

Can form oxides and hydroxides that are alkaline

Very reactive

Sodium (Na) is used in street lamps and it could be also used by our body alongside potassium to transfer electrical signals called nerve impulses

Density increases as you go down the group and their melting and boiling points also decrease, when they mix with water, they form a reaction.

Reactivity increases as you go down the table

When alkali metals are burnt in air, they produce metal oxides. On the other hand when they react with halogens, they produce halides.

Group 2: Alkaline Earth Metals

They can form oxides and hydroxides that dissolve slightly in water to make an alkaline solution.

Their density. melting and boiling points are higher than group 1 metals.

Their density increases as we go down the group while their melting and boiling points decreases.

Reactivity increases as you go down the group

Beryllium is used to make a mineral called beryl and beryllium also combines with other metals to make alloys.

Magnesium is used to make fireworks and alloys.

Group 7: Halogens

The melting and boiling point of halogens increases as you go down the group.

The reactivity of halogens decreases as you go down the group.

Fluorine is a pale yellow poisonous gas. it can be reacted with hydrogen to create hydrogen fluoride, it is used to etch glass surfaces.

Chlorine is used to kill bacteria in water supply systems

Group 8: Noble Gases

They are gases at room temperature, and very unreactive (inert)

Helium is lighter than air and it is used in meteorological balloons and oxygen tanks.

Neon is used in neon lights for advertising displays

Argon is used in wire filament bulbs, it replaces oxygen in light bulbs because it does not react with tungsten

Krypton is used in high intensity lights.

Xenon is used in flashlights for cameras or headlights for cars

Hydrogen

Its properties are not that compatible with other elements.

It is the lightest atom

A colorless gas without smell and it is highly flammable (easy to explode)

Future uses of hydrogen includes electrical vehicles and cars with a combustion engine.

Burning of hydrogen can produce electricity for hydrogen cars.