learn to write chemical formulas for ionic and covalent compounds using element symbols from the periodic table, including handling positive and negative ions.

Learn the three formula types—empirical, molecular, and structural—and how they express atom ratios, total atoms, and bonding, with examples like H2O, H2O2, SO2, PCl3, NO2, CO2, CO, CH4, and diamond.

Explore how simple covalent compounds are represented by molecular formulas, showing exact atom counts, subscripts, and water (H2O) as an example, contrasting with empirical formulas.

Discover how to write inorganic formulas by applying hydrogen conventions with nonmetals, using examples like H2O, H2S, and HCl, and noting hydrogen's placement for groups 3–5 versus 6–7.

Learn covalency and valence to write covalent formulas, exploring combining power, shared electrons, and why hydrogen, oxygen, and noble gases do not participate.

Explore how valency determines molecular formulas by balancing charges and deriving the simplest whole-number ratio, illustrated with CS2 and phosphorus compounds like PCl3 and PCl5.

Master the naming of simple inorganic molecules by using atom-count prefixes on the first and second elements, illustrated with dinitrogen pentoxide.

Develop your understanding of writing chemical formulas from prefixes mono, di, tri, and tetra, with practice on di nitrogen trioxide, dihydrogen monoxide, carbon disulfide CS2, and sulfur hexafluoride SF6.

Learn to write the formula of organic compounds by placing carbon first, then hydrogen, and arranging remaining elements alphabetically, including halogens such as chlorine and bromine.

Count carbon, hydrogen, nitrogen, oxygen, and sulfur from structural formulas to write molecular formulas. Arrange elements in alphabetical order after carbon and hydrogen, as shown with cystine.

Learn how ions form when atoms gain or lose electrons, creating cations and anions, with examples like sodium and fluorite, and a simple protons and electrons charge comparison.

This lecture defines ions and distinguishes cations from anions, then shows how sodium loses an electron to become a positive ion, while chlorine gains one to become a negative ion.

Identify cations and anions through a charges table, including plus one and plus three cations and minus one and minus two anions. Use these patterns to write chemical formulas.

The lesson defines monoatomic ions as single-atom species and polyatomic ions as covalently bonded groups of two or more atoms, with carbonate, hydroxide, ammonium, and phosphate as examples in compounds.

Define ionic compounds as oppositely charged ions bonded by electrostatic attraction, forming a crystal lattice, and show how to write formulas using sodium and chloride as examples.

Balance charges in diagrammatic representations to derive the empirical formula of ionic compounds from the cation–anion ratio, illustrated by sodium chloride and aluminium chloride.

Valency is the combining power equal to the charge carried when atoms gain or lose electrons, with group numbers mapping to plus or minus valencies.

Explore valency and combining power with the periodic table, showing how group 1 and hydrogen form +1 ions, nonmetals gain to complete octet, and transition metals exhibit variable valences.

master writing formulas for polyatomic ions by recognizing common anions and memorizing key ions such as acetate, nitrite, sulfite, chlorate, nitrate, sulfate, phosphate, and hydrogen carbonate, and their charges.

Balance charges to form the ionic formula for binary compounds, using Mg2+ and F- to yield MgF2, demonstrating subscripts that make total charge zero.

Apply the criss-cross method to write ionic formulas by swapping the valences of aluminium and oxygen, balancing charges to form aluminium oxide as a binary compound with proper subscripts.

Learn how to write ionic formulas for ternary compounds by balancing charges with polyatomic ions like magnesium and nitrate, using brackets for polyatomic groups and subscripts.

Learn to construct ionic formulas using the criss-cross method for binary and ternary compounds, balance charges, and apply brackets for ions such as PO4 3-.

Name ionic compounds by placing the cation first, then the anion, using -ide for monoatomic ions, and using polyatomic ion names for ternary compounds, with no prefixes.

Learn how to name ionic compounds using roman numerals for polyvalent and transition metals, balance charges to zero, and write formulas such as copper(II) sulfate and iron(III) oxide.

Develop your understanding of writing formulas and names for ionic compounds by practicing with potassium nitrate, magnesium nitrate, aluminium sulfide, ammonium phosphate, sodium hydrogen carbonate, and titanium oxide, applying valences.

Develop your understanding of writing ionic compound formulas using the criss-cross method and valences, with brackets for polyatomic ions, through examples like sodium phosphide and calcium nitrate.

Explore how to name and write chemical formulas for simple inorganic and organic compounds using conventions, alphabetical ordering, criss-cross ionic methods, and valency concepts for transition metals.