1. Create the following combinations of protons, neutrons, and electrons.1p, 1n, 1e a) What element is it? b) Is it charged? If so, what is its charge? c) Is it stable? Why or why not?

What if there are a different number of Neutrons? Sometimes elements have a different number of neutrons than usual, so therefore have a different atomic mass. This is what we call an Isotope (a variant form of an element which has the same number of protons but a differing number of neutrons). Sometimes we’ll see Isotopes labeled with their new mass like this: 14C = this is Carbon 14. Notice it has a different mass than what is on your periodic table The average mass of all the isotopes is defined as an element’s Atomic Weight. Can you answer questions about these Isotopes? ELEMENT ATOMIC MASS NUMBER OF PROTONS NUMBER OF NEUTRONS 14C A   B   C  15N D   E   F  2H G  H  I  Use your table to look up the number of protons, remember that never changes!

Iodine has 37 known isotopes.  Therefore, the atomic mass has a range of 108-144 amu. Which of the following statements concerning iodine is correct? A) The isotopes of iodine have between 55 and 91 protons. B) An atom of iodine can have between 55 and 91 neutrons. C) The isotopes of iodine will always have the same number of neutrons, but the protons can vary. D) The isotopes of iodine have between 108 and 144 neutrons, but the number of protons will not vary.

8. Predict which of the following organisms will have the highest percentage of unsaturated phospholipids in their membranes. A) Antarctic fish B) Desert snake C) Humans living in a temperate forest D) Thermophilic bacterium that lives in hot springs near 100°C Answer: Explanation:

1. The dipole moment in a water molecule Which statement about hydrogen bonds is NOT true? A) Hydrogen bonds account for the anomalously high boiling point of water. B) In liquid water, the average water molecule forms hydrogen bonds with three to four other water molecules. C) Individual hydrogen bonds are much weaker than covalent bonds. D) Individual hydrogen bonds in liquid water exist for many seconds and sometimes for minutes. E) The strength of a hydrogen bond depends on the linearity of the three atoms involved in the bond. 2. A TRUE statement about hydrophobic interactions is that they: A) are the driving force in the formation of micelles of amphipathic compounds in water. B) do not contribute to the structure of water-soluble proteins. C) have bonding energies of approximately 20-40 Kjoule per mole. D) involve the ability of water to denature proteins. E) primarily involve the effect of polar solutes on the entropy of aqueous systems.

. Give the name of and symbol for an element with this number of valence electrons.a) 2b) 6c) 8

How many protons, electrons, and neutrons are present in the following ? Magnesium cation (Mg2+), Chloride anion (Cl-),  Carbon -14(14C), and Tritium (3H)?

Some prokaryotic and all eukaryotic cells use oxygen to harvest energy from food molecules. In what form is that energy available to power cell work? a) b) c) glucose molecules d) fat molecules ATP molecules heat and light P Sunlight energy ECOSYSTEM Photosynthesis in chloroplasts Cellular respiration in mitochondria ATP (for cellular work) ww www Heat energy

Write the missing element in the following nuclear reactions. Include mass and atomic number. Type answer following this example: 237 U-237 Np + a. 73 Ga-73 Ge+ b. 192 Pt 188 Os+ C. 205 Bi-205 Pb+ (answer would be 92, 93, -Beta) d. 241Cm + 241 Am type your answer... type your answer... type your answer... type your answer....

What is the point group of the following molecule?                     A)D3h                                 B)C5v                               C)C1                                D)D2h                             E)C2h