Ch 2-The Chemical Context of Life

Question 1

Why Chemistry Important

Answer 1

• chemicals make up our bodies and those of other organisms

Question 2

Matter

Answer 2

• Matter
  
  • anything that takes up space & has mass
  • composed of elements

Question 3

Element

Answer 3

• 92 natural, 26 man-made
• Names are abbreviated by 1 or 2 letters
• Ex: C, O, H, Fe, Al, etc.
• Substances that cannot be broken down to other substances by chemical reactions

Question 4

Compounds

Answer 4

• Substance consisting of two or more elements in a fixed ratio
• different characteristics than elements

Question 5

Atoms

Answer 5

• The smallest particle of matter that still retains the properties of an element
• Consist of subatomic particles

Question 6

Molecules

Answer 6

• a group of atoms bonded together
• the smallest fundamental unit of a chemical compound

Question 7

Atomic number & Mass number

Answer 7

• Atomic number
  
  • number of protons in an atom
  • Written as a subscript to the left of chemical symbol
• Mass number
  
  • sum of the number of protons & neutrons
  • written as a superscript to the left of the chemical symbol

Question 8

Interrelationship between protons, neutrons, & electrons

Answer 8

Protons and neutrons are basically found at the atomic (atom) nucleus while elecctrons form the shell of the atom, moving around the nucleus.

Question 9

Electrons how to be donated or shared between atoms

Answer 9

Electrons can be transferred, shared, or cause charge disparities between atoms to create bonds, including ionic, covalent, and hydrogen bonds, as well as van der waals interactions.

Question 10

Compare & Contrast ionic, covalent, hydrogen bonds, van der waals interaction

Answer 10

Covalent bonds are the strongest, then ionic, hydrogen, Van der Waals

Question 11

Valence Cell

Answer 11

Are the outermost shells

Question 12

Innermost cell is full with how many electrons?

Answer 12

2 electrons

Question 13

2nd & 3rd cells can hold up to how many electrons?

Answer 13

8 electrons

Question 14

Chemically stable & reactive atom?

Answer 14

The stability of atoms depends on whether or not their outer-most shell is filled withe electrons.

Question 15

How atomic structure affects chemical bonding?

Answer 15

Interactions (or attractions) that hold atom close together.

Question 16

Electronegativity

Answer 16

Attraction for shared electrons

(more electronegative atoms pull harder)

Question 17

Polar and Nonpolar covalent bond

Answer 17

• Nonpolar
  
  • atoms share the electron equally
• Polar
  
  • one atom is more electonegative
  • atoms do not share the electron equally

Question 18

Biological significance of isotopes

Answer 18

• Nucleus decay spontaneously, giving off particles and energy
• radioactive tracers-diagnostic tools in medicine
  
  • used in imaging instruments