Chemical Names and Formulas

1. Chemical Names and Formulas • Formulas • For a molecular compound (only nonmetals), the formula shows the actual number of atoms of each element in a molecule. • For an ionic compound (metal + nonmetal), the formula represents a formula unit (simplest ratio of ions) of the compound.

2. Chemical Names and Formulas B. Ions • Atoms are neutral because they have equal numbers of protons and electrons. • Ions- positive or negative particles formed when atoms lose or gain electrons. • Cations are positive ions • Metals lose electrons to form (+) ions • Na⁺ Sodium ion lost one electron (e⁻) • Mg²⁺ Magnesium ions lost two electrons

3. Chemical Names and Compounds B. Ions 4. Anions are negative ions. • Nonmetals gain electrons to form (-) ions • Monatomic anions have –ide endings • Cl⁻ chloride ion gained one electron • O²⁻ oxide ion gained two electrons

4. Chemical Names and Formulas C. Charge of Ions • Main Group Elements (8 tall columns) • Group number shows the number of electrons in the outer energy level (use second digit for group 13 – 18) • Metalslose all their outer level electrons; nonmetals gain to get 8 outer level electrons.

6. Chemical Names and Compounds D. Li N O F Na Mg Al S Cl K Ca Br RbSr I Cs Ba

7. Chemical Names and Compounds 2. Transition Metals (short column) • Also called d-block • Most have more than one possible charge • Use Roman Numerals to show the charge of transition metals • Ag⁺, Zn²⁺, and Cd²⁺ have ONLY one possible charge and don’t get a Roman Numeral.

8. Chemical Names and Compounds D. Binary Ionic Compounds • Contain only two elements (metal + nonmetal) • (+) and (-) charges MUST balance • Positive ion (metal) written first • -ide ending usually indicates a binary compound

9. Chemical Names and Compounds 6. Naming Binary Ionic Compounds • Name of Metal + Name of Nonmetal (-ide) • CaBr₂ ____________________ Na²O ____________________ • Use Roman Numerals to show the charge of transition metals (except Ag, Zn, Cd) CuCl _____________________ CuCl₂ _____________________

10. Chemical Names and Compounds E. Polyatomic Ions • Polyatomic ions- group of atoms that act as one ion. • -iteending indicates one less oxygen than –ate; the charge will be the same. SO₄²⁻ SO₃²⁻ Sulfate ion Sulfite ion

11. Chemical Names and Compounds • Prefix per- means one more oxygen than -ate; prefix hypo- means one less oxygen than -ite. CIO₄⁻ Perchlorate CIO₃⁻ Chlorate CIO₂⁻ Chlorite CIO⁻ Hypochlorite • H⁺ + CO₃²⁻ => HCO₃⁻ Hydrogen Carbonate Hydrogen Carbonate

12. Chemical Names and Compounds F. Compounds Containing Polyatomic Ions • Use parentheses if subscript is added for the polyatomic ion. • Sodium Ammonium Carbonate _________ Sulfate _________ Calcium Magnesium Nitrate __________ Hydroxide __________

13. Chemical Names and Compounds G. Binary Molecular Compounds • Contain two nonmetals • Same two nonmetals can form several different compounds. • Use prefixes in name to show how many atoms of that element • Mono- 6. Hexa- • Di- 7. Hepta- • Tri- 8. Octa- • Tetra- 9. Nona- • Penta- 10. Deca-

14. Chemical Names and Compounds 4. CO₂ CO Carbon Dioxide Carbon Monoxide 5. Do not use mono- for the first element. 6. CBr₄ _______________ N₂O₅ _______________ PCl₃ _______________ N₂O _______________

15. Chemical Names and Compounds H. Acids – compounds which produce H⁺ ions in water. • Use prefix –hydro where there are only two elements. • Anion EndingsAcid Name -ide hydro-( )-ic acid -ate ( )-ic acid -ite ( )-ous acid

16. Chemical Names and Compounds 3. HCl _______________ H₂SO₄ _______________ HNO₃ _______________ Acetic Acid ____________ Phosphoric Acid ________ Carbonic Acid __________ • H₂SO₄ H₂SO₃ Sulfuric Acid Sulfurous Acid

17. Chemical Names and Compounds • Using Chemical Formulas • Formula Mass (amu) –sum of the atomic masses of all the atoms in the formula. • Molar Mass (g) – the mass of one mole of a substance. • Formula mass and molar mass are calculated the same way, but the units are different.

18. Chemical Names and Compounds • Calculate the formula mass and molar mass: Formula MassMolar Mass CO₂ ___________ amu ________ g Ba(NO₃)₂ _________ amu ________ g Calcium Chloride ___________ amu _________ g

19. E. Conversions • Molar Mass 6.022*10²³ Grams  moles  particles Names Of Particles 2. Most elements atoms H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂ molecules Molecular Compounds molecules Ionic Compounds formula units

20. 3. How many moles are in 4.55 grams of magnesium bromide? 4. How many oxygen molecules are in 32 moles of oxygen? 5. Find the mass of 3.4*10²⁵ molecules of methane (CH₄). 6. How many hydrogen atoms are in 89 g of water?

21. F. Percent Composition – the percent, by mass, of each element in the compound. • % composition from lab data Mass of element (100) • % element= Mass of compound • Calculate % composition if 29.0 grams of silver reacts with 4.30 grams of sulfur to form a compound • % Composition from the formula mass of element in 1 mol compound (100) % element= mass of 1 mol compounds 4. Find the % comp. of magnesium hydroxide.

22. Chemical Names and Compounds E. Determining Chemical Formulas- may or may not be correct molecular form. • Empirical Formula- Simplest whole number ratio of elements in the compound. • Find the empirical formula if 79.8 g carbon reacts with 20.2 g Hydrogen. • Convert grams to moles of atoms. • Find ratio of moles (divide each by the smallest) • Empirical Formula

23. Chemical Names and Compounds • Find the empirical formula if 25.9% N and 74.1% O. • Choose to use 100 g compound and convert grams to moles • Find Ratio of moles • Need whole number ratio for empirical formula

24. Molecular Formula – shows the actual number of atoms in the molecule • Molecular formula = (x) (empirical formula) Molar mass x= Empirical Mass 2. Determine the molecular formula if the empirical formula is CH₂ and the molar mass in 42.0

25. Molecular Formula – shows the actual number of atoms in the molecule 3. Determine the empirical formula and the molecular formula if 58.8% C, 9.8% H, and 31.4% O and the molar mass= 102g