Periodicity

How are elements arranged

Atomic number

Groups in the periodic table are…

Vertical columns within the table contain elements with similar chemical properties resulting from a common number of electrons in the outer shell

Periods in the periodic table are….

Rows of elements arranged with increasing atomic number, demonstrating an increasing number of outer electrons and a move from metallic to non-metallic characteristics

Which elements have metallic bonding (from first 20 elements)?

Metallic (Li, Be, Na, Mg, Al, K, Ca)

Which elements have covalent molecular bonding (from first 20 elements)?

H2, N2, O2, F2, Cl2, P4, S8 and fullerenes (eg C60)

Which elements have covalent network bonding (from first 20 elements)?

B, C (diamond, graphite), Si

Which elements are monatomic

Noble gases - group 0/8

What is the covalent radius?

Measure of the size of an atom- Half the distance between the nuclei of two covalently bonded atoms in an element

Trends of covalent radius =

Going across a period covalent radius decreases

Going down a group covalent radius increases

Define ionisation energy

The energy required to remove one mole of electrons from one mole of gaseous atoms (outermost electrons)

Trends of ionisation energies

Going across a period ionisation energy increases

Going down a group ionisation energy decreases

Define electronegativity

Measure of the attraction an atom involved in a bond has for the electrons of the bond.

Trends in electronegativity

Going across a period electronegativity increases

Going down a group electronegativity decreases