Iron(III) oxide checked as Fe2O3, dinitrogen pentoxide written N2O5 and sulfurous acid kept apart from sulfuric: the SC180 Unit 4 nomenclature exercise, item by item. Searches like "sc 180 unit 4 assignment example", "sc180 unit 4 sample" and "sc180 unit 4 example" land here.
What a finished SC180 Unit 4 nomenclature exercise looks like
The exercise is laid out as a table in five blocks, the given item on the left, the answer beside it and a narrow third column for the check. Ionic compounds with fixed charges open it: calcium phosphate becomes Ca3(PO4)2, with 3(+2) plus 2(-3) equal to zero written alongside and the parentheses explained as the way to multiply a polyatomic ion. Variable-charge metals follow, where Cu2S is named copper(I) sulfide because two copper ions balance one sulfide at -2. Molecular compounds switch to prefixes, sulfur hexafluoride and dinitrogen pentoxide, with a note that prefixes never appear in ionic names. The acids block contrasts HNO2, nitrous acid, with HNO3, nitric acid, and H2SO3 with H2SO4. Hydrates close it, copper(II) sulfate pentahydrate written with its five waters.
How a SC180 Unit 4 example is structured
A one-paragraph key opens the exercise and states the decision everything else depends on: is the compound ionic or molecular, and if ionic, does the metal have one possible charge or several? Every item is then answered in the order that question implies. Blocks progress from rules that need no judgment toward rules that need several at once, so acids, which combine an anion name with a suffix change, come late. Within each block, items alternate direction, name to formula and then formula to name, since graders check the two skills separately. A short polyatomic ion reference, the ten or so ions the course expects from memory, sits at the foot of the page rather than inside answers. Common confusions get a one-line note where they arise, chlorite against chlorate, or the -ide ending carried by hydroxide and cyanide.
Ionic or molecular, decided first
Each item is sorted by whether a metal is present before any naming begins, since that single decision determines whether prefixes or charges govern the answer.
Charges balanced in the margin
Every ionic formula carries its arithmetic, 2(+3) and 3(-2) summing to zero for Fe2O3, so a grader sees the formula was derived rather than remembered.
Roman numerals read from the anion
For copper, iron, tin and lead, the metal's charge is worked backward from the anion's total, and the numeral in the name reports that charge, never a subscript.
Prefixes for molecules only
Mono-, di-, penta- and hexa- appear in the molecular block and nowhere else, with the rule that mono- is dropped from the first element stated at the first example.
Acid names tied to anion endings
An -ate anion gives an -ic acid and an -ite anion an -ous acid. The block pairs each acid with its parent anion, so the naming reads as a rule rather than a list.
Where marks go in SC180 Unit 4
Losses cluster where ionic and molecular rules get mixed: a salt given prefixes, such as tricalcium diphosphate, or carbon dioxide written without one. Formula errors from skipped charge balancing come next, CaCl for calcium chloride or AlO for aluminum oxide, each of which a margin check would have caught. Roman numerals cause steady trouble, attached to sodium or zinc where the charge never varies, or copied from a subscript so that Fe2O3 becomes iron(II) oxide. Polyatomic ions lose their parentheses when multiplied, Ca3PO42 in place of Ca3(PO4)2. Acid names draw deductions when -ate and -ite endings are reversed, making nitrous and nitric acid interchangeable. Symbols typed with the wrong capitalization lose precision points in many sections, because CO written where cobalt was meant names carbon monoxide instead.
Get a SC180 Unit 4 example written to your instructions
Paste the Unit 4 list in its original order and direction, names or formulas, along with the SC180 rubric or any formatting rules for subscripts. Every item returns with its charge check or prefix note alongside, and polyatomic ions are flagged where the list uses them. The first sample costs nothing and lands in 24-48h.
SC180 Unit 4 questions, answered
How do I know when to use Roman numerals?
When the metal can form more than one ion, which in SC180 usually means the transition metals plus tin and lead. Group 1 and 2 metals, aluminum, zinc and silver have one common charge and take no numeral. The numeral states the charge on each metal ion, found by balancing the anion's total, and never the subscript.
Why is Ca3(PO4)2 written with parentheses?
Because the subscript 2 applies to the whole phosphate ion, not only its oxygen. Without parentheses, Ca3PO42 would read as forty-two oxygens or not read at all. Parentheses appear only when more than one polyatomic ion is needed, so sodium phosphate, Na3PO4, takes none. Graders treat a missing pair as a formula error, not a typing slip.
Do I need to memorize the polyatomic ions?
Most SC180 sections expect a core set from memory, commonly ammonium, hydroxide, nitrate, sulfate, carbonate, phosphate, acetate and a few others, and allow a reference for the rest. The -ate and -ite pattern cuts the load: knowing nitrate gives nitrite with one oxygen fewer, and the same holds for sulfate and sulfite.