C2 - The periodic table 1️⃣✅

Alkali metals

Because they react with water to form an alkali

A chemical that can dissolve in water, combine with acids to form salts, and make acids less acidic

By the number of electrons in its outer shell

Because there is only 1 electron in their outer shell, they only need to loose one electron to react

increases

Reactivity increases down group 1 because as you move down the group the atoms get larger therefore the outer electron gets further from the nucleus and the attraction between the nucleus and outer electron gets weaker – so the electron is more easily lost.

decreases

The halogens

By its number of shells

The halogens are non-metals that exist as molecules made up of pairs of atoms

decreases

increases

The Nobel gasses

• they have full outer shells with 8 electrons, so do not need to loose or gain electrons • they are very unreactive so exist as single atoms as they dont bond to form molecules • boiling points increase down the group

A displacement reaction occurs when a more reactive element displaces, or pushes out, a less reactive element from a compound that contains the less reactive element.

By atomic number

Due to atomic weights of existing atoms that he had already placed in his table

+1

+2

+3

0

-3

-2