Topic 2 - Periodic Table arrangement Flashcards
The periodic table is arranged in order of increasing
ATOMIC NUMBER
The columns of the periodic table are called
groups
The rows of the periodic table are called
periods
Elements with similar … are found in the same colum
PROPERTIES
The row an element is found in indicates the number of … in atoms of that element
ELECTRON SHELLS
The column an element is found in indicates the number of … in atoms of that element
OUTER SHELL ELECTRONS
Period 1
Only contains Hydrogen and Helium
Fills the 1s orbital
Helium has a full electron shell and is therefore unreactive
Hydrogen has only one electron and can gain or lose it to form positive or negative ions, or can undergo covalent bonding with other non-metals
Hydrogen is the most abundant element in the universe
Period 2 – Lithium to Neon
Contains 8 elements
Fills the 2s and 2p orbitals
Lithium and beryllium are reactive metals which form alkalis in water
Carbon has a giant molecular structure which can be diamond, graphite, graphene or fullerene
Nitrogen, Oxygen and fluorine are all diatomic molecules
Neon is a noble gas with full electron shells and is therefore unreactive
Period 3 – Sodium to Argon
Contains 8 elements
Fills the 3s and 3p orbitals
3 metals which form positive ions
3 non-metals which form negative ions
Argon is a noble gas so is unreactive
Period 4 – Potassium to Krypton
Contains 18 elements
Fills the 4s, 4p and 3d orbitals
Includes the first row of the transition metals (d block)
Periodic Table blocks
Element blocks are named for the orbital occupied by the highest energy electrons the elements contain
Group 1 and 2 make up the s-block (they have their outer electrons in the 1s, 2s, 3s etc orbitals)
Groups 3-7 and 0 make up the p-block (they have their outer electrons in the p-orbitals). This block contains all the non-metals apart from Hydrogen and Helium
The transition metals make up the d-block
Recap – Electron structures
Electrons fill the lowest energy shells first (Aufbau principle)
The closer the shell is to the nucleus, the lower the energy
So electrons fill from the nucleus out.
Electrons repel each other as they have the same charge so they will occupy different sub-shells within an orbital if possible