Q: How do atoms of different elements combine to form compounds? Q: How are ionic bonds formed? Q: What is an ion? Q: How is a sodium ion, Na+, form from a sodium atom? Q: How is a chloride ion, Cl-, formed from a chlorine atom? Q: How do atoms of Group 1 elements form ions? Q: How do atoms of Group 2 elements form ions? Q: How do atoms of Group 6 elements form ions?

A: By the transfer of electrons to form cations and anions. A: By the formation of new chemical bonds. A: By the loss of one (the outer) electron. A: Atoms or groups of atoms with a positive or negative charge. A: By the loss of the one electron in their outermost electron shell, to give a 1+ ion. A: By the gain of one electron into its outermost shell. A: By the addition of two electrons to their outermost electron shell, to give a 2- ion. A: By the loss of the two electrons in their outermost electron shell, to give a 2+ ion.

Q: How do atoms of Group 7 form ions? Q: What does the ending –ide mean in the name of an ionic compound? Q: What does the ending –ate mean in the name of an ionic compound? Q: What are the chemical formulae for: sodium chloride, sodium oxide, sodium hydroxide? Q: What are the chemical formulae for: calcium nitrate, calcium sulfate, calcium carbonate? Q: What are the chemical formulae for: aluminium chloride, ammonium sulfate, iron(III) oxide? Q: What is meant by the term ‘lattice structure’? Q: Describe and explain the melting points of sodium chloride and magnesium oxide.

A: The anion contains only one type of atom (except for hydroxides). A: By the addition of one electron to their outermost electron shell, to give 1- ions. A: NaCl, Na2O, NaOH. A: The anion contains two or more different elements and one of them is oxygen (except for hydroxides). A: AlCl3, (NH4)2SO4, Fe2O3. A: Ca(NO3)2, CaSO4, CaCO3. A: High melting and boiling points due to the very strong bonds between the ions – it takes a lot of energy to break these bonds. A: A structure consisting of a regular arrangement of ions, held together by strong electrostatic forces (ionic bonds) between oppositely-charged ions.

Q: Describe and explain the electrical conductivity of ionic compounds. Q: Describe the solubility in water of sodium, potassium and ammonium salts. Q: Describe the solubility in water of nitrate salts. Q: Describe the solubility in water of chloride salts. Q: Describe the solubility in water of sulfate salts. Q: Describe the solubility in water of carbonates and hydroxides. Q: What is a precipitation reaction? Q: What is a precipitate?

A: All common salts are soluble. A: They conduct electricity when aqueous or molten, as in these states the ions are free to move so they can carry electric current. A: All common salts are soluble, except silver and lead. A: All are soluble. A: All common salts are insoluble, except for sodium, potassium and ammonium. A: All common salts are soluble, except lead, barium and calcium. A: Insoluble solid in a solution during a chemical reaction. A: A reaction that results in an insoluble product.

Q: What is a barium meal? Q: Why is barium sulfate used in barium meals? Q: Describe the results of flame tests for solids or solutions containing the following ions: Na+, K+, Ca2+, Cu2+. Q: What is the test for carbonate ions? Q: What is the test for sulfate ions? Q: What is the test for chloride ions? Q: What is spectroscopy and what is it used for? Q: Name two elements discovered through spectroscopy.

A: Barium sulfate swallowed just before an X-ray. A: It is opaque to X-rays; it is safe to use as, although barium salts are toxic, its insolubility prevents it entering the blood. A: Barium sulfate swallowed just before an X-ray. A: Add dilute acid. If carbonate is present, CO2 gas will be produced. You can test for this by bubbling through limewater – it turns milky in the presence of CO2. A: Na+ = yellow/orange flame. K+ = lilac flame. Ca2+ = brick-red flame. Cu2+ = blue-green flame. A: Add dilute HNO3, followed by silver nitrate solution. A chloride gives a white precipitate of silver chloride. A: Add dilute HCl, followed by barium chloride solution. A white precipitate of barium sulfate means the original compound was a sulfate. A: Rubidium and caesium. A: A sophisticated flame test: substances are heated until they produce their own unique emission spectrum; used to detect very small amounts of elements.