The Periodic Table

What is the periodic table?

• The periodic table is the elements organised in order of $increasing atomic number$
• Arranged into $groups$ and $periods$
• $Periodic$: regular intervals

Groups

Columns going $down$

Same group: similar $chemical properties$

Same number of $electrons$ on their $outer shell$

8 Groups

• i: $Alkali metals$
• ii: $Alkaline earth metal$
• iii: $Transition metals$
• vii: $Halogens$
• viii: $Noble inert gases$

Periods

Rows going $across$

Labelled => N=1 to N=7

Same period: Same number of $orbits$/shells

Important terms

Isotope

Atoms of the $same element$ that have $different number of neutrons$

Example: Carbon

Stability

Elements that have a full outer shell => very $unreactive$

Octet Rule

Atoms must have a full outer shell ($8$)

Molecules

A molecule is a group of atoms joined together. It is the smallest particle of an element or compound that can exist independently

Example: Hydrogen (H2) and Water (H2O)

Chemical bond: force holding atom together

Ionic bonding

Ion: charged atom or group of atoms

Ionic bonding steal or give an electron

• If an atom gives away an electron => positively charged +
• If an atom receives/steals an atom => negatively charged -

Example: Sodium chloride => NaCl

Covalent Bonding

Sharing electrons

Example: water => H2O

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