Welcome to Chem 1A with Terri Bentzinger

1. Welcome to Chem 1Awith Terri Bentzinger E-mail: benzene4president@gmail.com Website: http://clas.sa.ucsb.edu/staff/terri/ Drop-in: M thru R, 1-2, SRB Rm 3274

2. Atoms – Molecules - Ions 1. What does the atomic number tell you about an atom? What is the atomic number of sulfur? Atomic number tells you the number of protons in any one element – can be found on the periodic table Sulfur has an atomic number of 16

3. Atoms – Molecules - Ions 3. Define mass number. What is the mass number for potassium? Mass number is the total number of protons and neutrons in any one isotope – can not be found on the periodic table Since the mass number is not on periodic table we can not answer the second question without further resources

4. Atoms – Molecules - Ions 3. What are isotopes? – Isotopes are atoms of the same element with varying number of neutrons

5. Atoms – Molecules - Ions 4. What is atomic mass for chlorine? How is the atomic mass calculated? Atomic mass of chlorine is 35.45 – atomic masses are calculated by taking the average of the naturally occurring isotopes based on their relative abundances

6. Atoms – Molecules - Ions 5. What are ions? How are ions generated? Ions are atoms or groups of atoms with a net charge – Ions are generated by the gain or loss of electrons – gaining an electron causes a net negative charge a.k.a. an anion – losing an electron causes a net positive charge a.k.a. a cation

7. Atoms – Molecules - Ions 6. Metals tend to gain orlose electrons? What charge do group 1 metals form? 1+ What charge do group 2 metals form? 2+

8. Atoms – Molecules - Ions 7. Non-metals tend to gainor lose electrons? What charge do group 5 non-metals form? 3- What charge do group 6 non-metals form? 2- What charge do group 7 non-metals form? 1- What charge do group 8 non-metals form? 0

9. Atoms – Molecules - Ions 8. What’s the difference between elements, compounds, atoms and molecules? Elements are the simplest of the pure substances and can not be chemically broken down – Compounds are 2 or more elements chemically bonded to each other – atoms are the smallest stable particles that make up an element – molecules are 2 or more nonmetallic atoms bonded to each other

10. Atoms – Molecules - Ions 9. Fill in the following table:

11. Atoms – Molecules - Ions 10. How could you distinguish between ionic compounds, covalent compounds and acids? Ionic compounds have a cation and an anion – the cation is more often than not a metal with the exception of ammonium ion (NH4+) – Covalent compounds are made up of 2 or more nonmetals – Acids start with hydrogen

12. Atoms – Molecules - Ions 11. The fact that nitrogen and oxygen can form multiple compounds such as NO, N2O, NO2 and N2O5 is an example of which law? Law of multiple proportions

13. Atoms – Molecules - Ions 12. Name and label the type of compound for each of the following: a. LiHCO3lithium bicarbonate g. HClO hypochlorous acid b. Na2SO3sodium sulfite h. HNO3 nitric acid c. (NH4)3PO4ammonium phosphatei. SF6 sulfur hexafluoride d. Fe(OH)3iron(III) hydroxide j. CO carbon monoxide e. CuBr copper(I) bromide k. P2O5 diphosphorus pentoxide f. HF hydrofluoric acid l. NCl3 nitrogen trichloride

14. Atoms – Molecules - Ions 13. Write the chemical formulas for the following compounds: a. calcium cyanide Ca(CN)2 b. aluminum sulfate Al2(SO4)3 c. lead(IV) permanganate Pb(MnO4)4 d. hydrosulfuric acid H2S e. sulfuric acid H2SO4 f. bromous acid HBrO2 g. sulfur trioxide SO3 h. carbon tetrachloride CCl4

15. Atoms – Molecules - Ions 14. Here are some common names that you’re expected to know; write the chemical formula. a. Water H2O b. Methane CH4 c. Ammonia NH3