Question

model 2 - prefixes and suffixes
prefix numerical value
mono- 1
di- 2
tri- 3
tera- 4
penta- 5
hexa- 6
hepta- 7
octa- 8
nona- 9
deca- 10
molecular formula name of comp
bcl₃ boron trichloride
sf₆ sulfur hexafluoride
if₇ iodine heptafluoride
ni₃ nitrogen triiodide
n₂o₄ dinitrogen tetroxide
cl₂o dichlorine monoxide
p₄o₁₀ tetraphosphorus decoxide
b₅h₉ pentaboron nonahydride
br₃o₈ tribromine octoxide
clf chlorine monofluoride

1. what ending do all the compound names have in common?
2. when is a prefix not used in front of the name of the first element?
3. use the prefixes to name each of the following compounds:

molecular formula molecule name
pbr₃
scl₄
n₂f₂
so₃
brf

1. use the names to write the formula for each of the compounds below:

molecular formula molecule name
disulfur decafluoride
carbon tetrachloride
oxygen difluoride
dinitrogen trioxide
tetraphosphorus heptasulfide

Explanation:

1. All the compound names end with -ide. This is a common naming convention for binary molecular compounds where the second - element is named with an -ide ending.
2. A prefix is not used in front of the name of the first element when there is only one atom of the first - element in the compound. For example, in CO₂, carbon is the first element and since there is one carbon atom, no prefix is used for carbon.

9)

• PBr₃: Phosphorus tribromide (since there is 1 phosphorus and 3 bromine atoms, 'tri -' is used for 3).
• SCl₄: Sulfur tetrachloride ('tetra -' for 4 chlorine atoms).
• N₂F₂: Dinitrogen difluoride ('di -' for 2 nitrogen and 2 fluorine atoms).
• SO₃: Sulfur trioxide ('tri -' for 3 oxygen atoms).
• BrF: Bromine monofluoride ('mono -' for 1 fluorine atom).

10)

• Disulfur decafluoride: S₂F₁₀ (di - means 2 for sulfur and deca - means 10 for fluorine).
• Carbon tetrachloride: CCl₄ (tetra - means 4 for chlorine).
• Oxygen difluoride: OF₂ (di - means 2 for fluorine).
• Dinitrogen trioxide: N₂O₃ (di - means 2 for nitrogen and tri - means 3 for oxygen).
• Tetraphosphorus heptasulfide: P₄S₇ (tetra - means 4 for phosphorus and hepta - means 7 for sulfur).

Answer:

1. -ide
2. When there is only one atom of the first element in the compound.
3. Phosphorus tribromide, Sulfur tetrachloride, Dinitrogen difluoride, Sulfur trioxide, Bromine monofluoride
4. S₂F₁₀, CCl₄, OF₂, N₂O₃, P₄S₇