Exam 1: Unit 2

Question 1

Matter

Answer 1

• The stuff of the universe.

Question 2

Element

Answer 2

• Simplest form of matter with unique chemical properties.

Question 3

Atom

Answer 3

• The smallest possible piece of an element

Question 4

Atomic Number of Each Element

Answer 4

• The number of protons in its nuclues

Question 5

Periodic Table

Answer 5

• Letter symbols of elements arranged by atomic number.

Question 6

Nucleus

Answer 6

• Center of atom contains:
  
  • Protons: Positive charge, mass of 1 amu.
  • Neutrons: Neutral charge, mass of 1 amu.
  • Atomic mass: = total number of protons + neutrons.

Question 7

Electron Shells

Answer 7

• Electrons: negative charge
• # of electrons = = of protons, atoms have neutral charge.
• Electrons further from nucleus have higher energy.
• Valence electrons are in the outtermost shell.
  
  • Interact with other atoms.
  • Determine chemical beghavior.
  • Octet rule - atoms react to obtain a stable number of 8 valence electrons.

Question 8

Isotopes

Answer 8

• Elements that differ in the number of neutrons: 1H, 2H, 3H: extra neurtons result in increased atomic weight. (Heavy water): have no chnage in chemical behavior: (same valence electrons)

Question 9

Atomic Weight

Answer 9

• Average atomic mass of the mixture of isotopes of an element found in a sample.

Question 10

Ions

Answer 10

• Carry a charge, unequal numbers of protons and electrons.

Question 11

Ionization

Answer 11

• Transfer of electrons from one atom to another ( ^ Stabliity of valenec shell)

Question 12

Anion

Answer 12

• Atom gained electron, net negative charge

Question 13

Cation

Answer 13

• Atom lost an electron, net positive charge.

Question 14

Electrolytes (ions)

Answer 14

• Salts that ionize in water, form solutions capable of conducting electicity.
• Bodies most adundant electrolytes.
  
  • Na+, Ca2+, Mg2+, Cl-, PO43, and HCO3-.
• Essential to nerve and muscle function.
• Imbalance effects range from muscle cramps, brittle bones to coma and death.

Question 15

Free Radicals

Answer 15

• A particle with an odd number of elecrons: superoxide anion O2-: Oxygen molecule with an extra electron.
• Produced by metabolic reacitons, radiation, and chemicals.
• Causes tissue damage: triggers chain reactions that destroy molecules.
• Antioxidants: neutralize free radicals. (SOD - superoxide dismutase enzyme): vitamin E, carotenoids, vitamin C

Question 16

Molecules

Answer 16

• Two or more atoms of same element covalently bonded.

Question 17

Compound

Answer 17

*Two or more atoms of different elements of covalently bonded.

Question 18

Ionic Bonds

Answer 18

• Attraction of oppositely charges ions to each other forms an ionic bond - no sharing of electrons.
• Ionic bonds are weak and dissocaite in water.
• These compunds tend to form crystals.

Question 19

Covalent Bonds

Answer 19

• Formed by sharing valence electrons.
• Types of covalent bonds:
  • Single covalent bond
  • Double covalent bonds
  • Nonpolar covalent bonds
  • Polar covalent bonds

Question 20

Single Covalent Bond

Answer 20

*One pair of electrons are shared.

Question 21

Double Covalent Bond

Answer 21

• Two Pairs of electorns are shared with each C=O bond.

Question 22

Nonpolar Covalent Bonds

Answer 22

*Electrons shraed equally

Question 23

Polar Covalent Bond

Answer 23

• Electrons shared unequally.

Question 24

Hydrogen Bonds

Answer 24

• Weakest of the bonds.
• Attaction between polar molecules - no sharing of electrons.
• Greatest physiologival importance:

Question 25

Acid

Answer 25

• Molecule or compound that donates a H+ ion.

Question 26

Base

Answer 26

• Molecule or compound that accepts a H+ ion.