deca = ten
decagon
deck
december
nona = nine
nonagenerian
nonagon
nonabsorbant
octo = eight
octopus
octogon
octoganol
hept = 7
heptagon
heptameters

heptagonal
hex = six
cathexis
hex
hexachlorethane
penta = five
pentagon
pentagram
pentateuch
tetra = four
allotetraploid
hexamethylenetetramines
oxytetracycline
tri = three
tricycle
tripod
triceratops
di = two
dictionary
dictator
diocese
mono = one
monolith
ammono
monopoly
neon
ne
10
calcium
ca
20
flurine
f
9
potassium
k
19
argon
ar
18
oxegyn
o
8
nitrogen
n
7
chlorine
ci
17
Sulfur
S
16
Carbon
6
C
Boron
B
5
phosphorous
P
15