What’s on the Writing Formulae poster
A 7-row table: Ion · Formula · Charge.
Common polyatomic ions.
- Hydroxide — OH — −1
- Nitrate — NO₃ — −1
- Carbonate — CO₃ — −2
- Sulfate — SO₄ — −2
- Phosphate — PO₄ — −3
- Ammonium — NH₄ — +1
- Hydrogencarbonate — HCO₃ — −1
Calcium (2+) and nitrate (1−) give Ca(NO₃)₂ — brackets because the whole ion is doubled, not the nitrogen.
Questions about the Writing Formulae poster
- What’s on the Writing Formulae poster?
- A 7-row table: Ion · Formula · Charge. Common polyatomic ions. Hydroxide — OH — −1; Nitrate — NO₃ — −1; Carbonate — CO₃ — −2; Sulfate — SO₄ — −2; Phosphate — PO₄ — −3; Ammonium — NH₄ — +1; Hydrogencarbonate — HCO₃ — −1. Calcium (2+) and nitrate (1−) give Ca(NO₃)₂ — brackets because the whole ion is doubled, not the nitrogen.
- Who is the Writing Formulae poster for?
- Writing Formulae belongs to the Chemistry section rather than to a school year, because physical science is not something one grade owns. Anyone learning general chemistry can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Writing Formulae poster?
- Cross the charges over and simplify. That gives the formula every time. A wall chart earns its place by being glanceable from where the work is happening, so Writing Formulae belongs on the wall where that physical science work actually happens, within glancing distance, rather than filed away.
- What other posters go with Writing Formulae?
- Acids & Bases, Atomic Structure and Balancing Equations sit alongside Writing Formulae in the Chemistry section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Acids & BasesAtomic StructureBalancing Equations
- Is the Writing Formulae poster free to download and print?
- Yes. Writing Formulae downloads as a free PDF with no account, no email and no watermark, like everything else in the Chemistry section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Writing Formulae poster print at?
- Writing Formulae is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Writing Formulae loses nothing.Printing guide
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