Deca=10
decade
decagon
decane
Nonagon
Nonagenarian
Nonigravida
octuple
octave
octopus
heptagon
heptarchy
heptameter
hexagon
hexavalent
hexarchy
Pentaprism
Pentagon
Pentameter
trialogue
triplications
triplets
monotheism
monochromatic
monodynamic
Neon
Ne
10
![](http://www.portlandschools.org/CTS/GrantsProjects/driscc/elements/neon/neon%20bohr%20model)
calsium
ca
20
Flourine
symbol: F
Atomic number: 9
Potassium
symbol: K
Atomic number: 19
Oxygen
symbol: O
atomic number : 8
Argon
symbol: Ar
atomic number:18
Nitrogen
N
7
Chlorine
Cl
17
Carbon
C
6
![](http://themadhatcher.com/wordpress/wp-content/uploads/2008/11/carbon_lab_eng.jpg)
Sulfur
S
16
Phosphorus
P
15
Boron
B
5